Reading in data from Text file

i have got that problem again and well i cant spot it maybe someone here can spot it ive been looking for ages;

Code:

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    printf("\n Please Enter the number of stops 0-3: ");
              scanf("%5d",&numstops);
              if(numstops>0)
              {
                  for(i=0;i<numstops;i++)
                  {
                  printf("\n Please enter the name for Stop %-1d: ",i+1);
                  scanf("%16s",&stopname[i]);
                  if( strcmp( stopname[i], "London" ) == 0 ){stops[i]=0;}
                  else if( strcmp( stopname[i], "Bath" ) == 0 ){stops[i]=1;}
                  else if( strcmp( stopname[i], "Cardiff" ) == 0 ){stops[i]=2;}
                  else if( strcmp( stopname[i], "Carlisle" ) == 0 ){stops[i]=3;}
                  else if( strcmp( stopname[i], "Durham" ) == 0 ){stops[i]=4;}
                  else if( strcmp( stopname[i], "Exeter" ) == 0 ){stops[i]=5;}
                  else if( strcmp( stopname[i], "Leeds" ) == 0 ){stops[i]=6;}
                  else if( strcmp( stopname[i], "Norwich" ) == 0 ){stops[i]=7;}
                  else if( strcmp( stopname[i], "Truno" ) == 0 ){stops[i]=8;}
                  else if( strcmp( stopname[i], "York" ) == 0 ){stops[i]=9;}
                  else{printf("\n Invalid place please Re enter: ");i--;}
                  }

                    if(numstops==1)
                      {
                      printf("\n Starting from %s To %s is %d miles",pos[0],stopname[0],chart[point[0]][stops[0]]);
                      printf("\n From %s To %s is %d miles",stopname[0],pos[1],chart[point[1]][stops[0]]);
                      printf("\n Total Distance : %-5d",chart[point[0]][stops[0]]+chart[point[1]][stops[0]]);
                      }
                      else if(numstops==2)
                      {
                      printf("\n Starting from %s To %s is %d miles",pos[0],stopname[0],chart[point[0]][stops[0]]);
                      printf("\n From %s To %s is %d miles",stopname[0],stopname[1],chart[stops[0]][stops[1]]);
                      printf("\n From %s To %s is %d miles",stopname[1],pos[1],chart[point[1]][stops[1]]);
                      printf("\n Total Distance : %-5d",chart[point[0]][stops[0]]+chart[stops[0]][stops[1]]+chart[point[1]][stops[1]]);
                      }
                 
                      else if(numstops==3)
                      {
                      printf("\n Starting from %s To %s is %d miles",pos[0],stopname[0],chart[point[0]][stops[0]]);
                      printf("\n From %s To %s is %d miles",stopname[0],stopname[1],chart[stops[0]][stops[1]]);
                      printf("\n From %s To %s is %d miles",stopname[1],stopname[2],chart[point[0]][stops[2]]);
                      printf("\n From %s To %s is %d miles",stopname[2],pos[1],chart[point[1]][stops[2]]);
                      printf("\n Total Distance : %-5d",chart[point[0]][stops[0]]+chart[point[0]][stops[1]]+chart[point[0]][stops[2]]+chart[point[1]][stops[2]]);
                      }
 
              }

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pos is declared as

Code:

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  char pos[1][16];
  char stopname[2][16];

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its when someone puts in for 3 stops i get this output
i put in london as my starting place but on the output for 3 stops i get a diff place name when i call upon it

http://i57.photobucket.com/albums/g2...k/Untitled.jpg

thankyou

Code:

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char stopname[2][16];

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With that declaration, you only get two elements in stopname. stopname[0] and stopname[1]. Don't try to access stopname[2] or you'll run into trouble.

Remember, an array like this

Code:

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type arrayname[N];

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has N elements. But because [0] is the first element, [N-1] is the last element. [N] is out of bounds.

Code:

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                  scanf("%16s",&stopname[i]);

---

Should not have the &.

I don't think that's the real problem tho'.

If Truno is Truro, then I think the distance is also quite wrong - Truro to Bath should be 345 miles. It looks like you get the Cardiff to Bath distance instead.

By the way, why not have a table of the city names and use a function to translate a city name to a number?

--
Mats

Quote:

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Originally Posted by matsp

Code:

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                  scanf("%16s",&stopname[i]);

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Should not have the &.

I don't think that's the real problem tho'.

If Truno is Truro, then I think the distance is also quite wrong - Truro to Bath should be 345 miles. It looks like you get the Cardiff to Bath distance instead.

By the way, why not have a table of the city names and use a function to translate a city name to a number?

--
Mats

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yea the spelling is messed and well im really new to C and just trying to do the rquirements how would you go about using a function


i still need to get a few more elements out of the program done like reading in the table from a text file and storing in a string array then i can tone down the code and add fancy bits to it......
i think i will have the program done in a day or 2 and well then ill post it and the requirements and ill see what everyone thinks and see how i can make it better

right i have got my program working all it needs to do is import this data and store in a string array

Code:

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        London        Bath        Cardiff        Carlisle        Durham        Exeter        Leeds        Norwich        Truro        York
London        -        23        12        89        456        123        46        732        345        123
Bath        23        -        46        234        123        46        89        234        567        90
Cardiff        12        46        -        767        456        46        234        123        732        35
Carlisle        89        234        767        -        732        32        48        67        98        100
Durham        456        123        456        732        -        234        46        89        89        732
Exeter        123        46        46        32        234        -        123        46        123        234
Leeds        46        89        234        48        46        123        -        46        89        19
Norwich        732        234        123        67        89        46        46        -        123        732
Truro        345        567        732        98        89        123        89        123        -        78
York        123        90        35        100        732        234        19        732        78        -

---

right these are the requirements for my program:

Initialise: Reads items from data file and stores in appropriate data structures. 10 place names and distances between them.
Menu: Displays options and validates selection with appropriate error messaging
Option selection calls correct function and exit functions correctly
DispChart: Displays chart showing distances between all points available
CalcDistance: Enables input of two points and up to 3 intermediate points and returns total distance and distance of each leg of the journey
Calls PlaceSearch function and prompts for re-entry on detection of invalid place name
PlaceSearch: Detects valid and invalid place names
Totalcost: Returns the cost of a journey between two points @ 40ppm (<=100) and 30ppm (>100)
Test Plan: Black box test identification
Test plan showing data and BB tests implemented.
Design: Abstract solution using pseudocode to represent functionality
Robustness and Data Validation: General attention to validation , formatting, clear screen and layout of screen display ,
Overall Impression: To include the use of appropriate data types, operators and control structures (selection, repetition), the structure of the code, the use of separate functions, the use of parameters and pointers where appropriate and the scope of successful implementation


and well after a few weeks of doin bits to it i still havent got it to import from text file and i feel like i have too much if statements well have a look and fiddle and give your advice on how i can improve ... thankyou

Code:

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// C Programming Assingment
#include <stdio.h>
#include <stdlib.h>
int strcmp( const char *str1, const char *str2 );
int main (void)
{
  int choice, row, col, i, numstops;
  int stops[2], point[2];
  char pos[2][16];
  char stopname[3][16];
   
  char chart1[11][11][11] ={ // Array for the Table and Plot points
  "-", "London", "Bath", "Cardiff", "Carlisle", "Durham", "Exeter", "Leeds", "Norwich", "Truno", "York",
  "London", "-", "23", "12", "89", "456", "123", "46", "732", "345", "123",
  "Bath", "23", "-", "46", "234", "123", "46", "89", "234", "567", "90",
  "Cardiff", "12", "46", "-", "767", "456", "46", "234", "123", "732", "35",
  "Carlisle", "89", "234", "767", "-", "732", "32", "48", "67", "98", "100",
  "Durham", "456", "123", "456", "732", "-", "234", "46", "89", "89", "732",
  "Exeter", "123", "46", "46", "32", "234", "-", "123", "46", "123","234",
  "Leeds", "46", "89", "234", "48", "46", "123", "-", "46", "89", "19",
  "Norwich", "732", "234", "123", "67", "89", "46", "46", "-", "123", "732",
  "Truro", "345", "567", "732", "98", "89", "123", "89", "123", "-", "78",
  "York", "123", "90", "35", "100", "732", "234", "19", "732", "78", "-"};
   
  int chart [10][10] = { // Array for the Table and Plot points
  {0,23,12,89,456,123,46,732,345,123},
  {23,0,46,234,123,46,89,234,567,90},
  {12,46,0,767,456,46,234,123,732,35},
  {89,234,767,0,732,32,48,67,98,100},
  {456,123,456,732,0,234,46,89,89,732},
  {123,46,46,32,234,0,123,46,123,234},
  {46,89,234,48,46,123,0,46,89,19},
  {732,234,123,67,89,46,46,0,123,732},
  {345,567,732,98,89,123,89,123,0,78},
  {123,90,35,100,732,234,19,732,78}
    }; 
   
   
        // menu
        printf("\n ============================================");
        printf("\n      M          E          N          U    ");
        printf("\n ================++++++++++++================");
        printf("\n 1. Display a complete mileage chart        ");
        printf("\n 2. Calculate the distance of your journey  ");
        printf("\n 3. Calculate the cost of your journey      ");
        printf("\n 4. Exit                                    ");
        printf("\n --------------------------------------------");
        printf("\n\n Please input your choice from the menu:  ");
        scanf("&#37;d", &choice);
       
    printf("\n\n");
       
        for(i=0;i<1;i++)
    {
              if(choice < 1 | choice > 4) // if the menu choice is invalid the program will ask the user to re input it.
              {
          printf("\nInvalid choice please re enter:  ");
              scanf("%d", &choice);
          i--;       
                }
    }
       
       
  switch (choice) // using a switch statement for the menu choice
  {
    case 1:

              printf("\n The first row and first column are plot points");
              printf("\n The mileage chart: \n\n");
 
              for(row=0; row<11;row++) // outputs the array in  2 loops
              {                 
                      printf("\n\n"); 
                      for(col=0;col<11;col++)
                      {
                        printf("%-10s",chart1[row][col]);
                      }
                   
              }
              printf("\n\n\n\n\n");
                          main();//  calls the main method once finshed
              break;


    case 2:
            printf(" 1: London\n 2: Bath\n 3: Cardiff\n 4: Carlisle\n 5: Durham\n 6: Exeter\n 7: Leeds\n 8: Norwich\n 9: Truro\n 0: York\n -------------------\n\n");         
            for(i=0;i<2;i++)
            {
              if(i==0){printf("\n Please enter your Start point: ");} // input first point
              if(i==1){printf("\n Please enter your Finishing point: ");} // input first point       
              scanf("%16s", pos[i]);
                      if( strcmp( pos[i], "London" ) == 0 ){point[i]=0;}
            else if( strcmp( pos[i], "Bath" ) == 0  ){point[i]=1;}
            else if( strcmp( pos[i], "Cardiff" ) == 0 ){point[i]=2;}
            else if( strcmp( pos[i], "Carlisle" ) == 0 ){point[i]=3;}
            else if( strcmp( pos[i], "Durham" ) == 0 ){point[i]=4;}
            else if( strcmp( pos[i], "Exeter" ) == 0 ){point[i]=5;}
            else if( strcmp( pos[i], "Leeds" ) == 0 ){point[i]=6;}
            else if( strcmp( pos[i], "Norwich" ) == 0 ){point[i]=7;}
            else if( strcmp( pos[i], "Truro" ) == 0 ){point[i]=8;}
            else if( strcmp( pos[i], "York" ) == 0 ){point[i]=9;}
            else{printf(" Invalid place please Re enter");i--;}
            }
           
           
           
           
           
            printf("\n Please Enter the number of stops 0-3: ");
              scanf("%5d",&numstops);
              if(numstops>0)
              {
                  for(i=0;i<numstops;i++)
                  {
                  printf("\n Please enter the name for Stop %-1d: ",i+1);
                  scanf("%16s",stopname[i]);
                  if( strcmp( stopname[i], "London" ) == 0 ){stops[i]=0;}
                  else if( strcmp( stopname[i], "Bath" ) == 0 ){stops[i]=1;}
                  else if( strcmp( stopname[i], "Cardiff" ) == 0 ){stops[i]=2;}
                  else if( strcmp( stopname[i], "Carlisle" ) == 0 ){stops[i]=3;}
                  else if( strcmp( stopname[i], "Durham" ) == 0 ){stops[i]=4;}
                  else if( strcmp( stopname[i], "Exeter" ) == 0 ){stops[i]=5;}
                  else if( strcmp( stopname[i], "Leeds" ) == 0 ){stops[i]=6;}
                  else if( strcmp( stopname[i], "Norwich" ) == 0 ){stops[i]=7;}
                  else if( strcmp( stopname[i], "Truro" ) == 0 ){stops[i]=8;}
                  else if( strcmp( stopname[i], "York" ) == 0 ){stops[i]=9;}
                  else{printf("\n Invalid place please Re enter: ");i--;}
                  }

                    if(numstops==1)
                      {
                      printf("\n Starting from %s To %s is %d miles",pos[0],stopname[0],chart[point[0]][stops[0]]);
                      printf("\n From %s To %s is %d miles",stopname[0],pos[1],chart[point[1]][stops[0]]);
                      printf("\n Total Distance : %-5d",chart[point[0]][stops[0]]+chart[point[1]][stops[0]]);
                      }
                      else if(numstops==2)
                      {
                      printf("\n Starting from %s To %s is %d miles",pos[0],stopname[0],chart[point[0]][stops[0]]);
                      printf("\n From %s To %s is %d miles",stopname[0],stopname[1],chart[stops[0]][stops[1]]);
                      printf("\n From %s To %s is %d miles",stopname[1],pos[1],chart[point[1]][stops[1]]);
                      printf("\n Total Distance : %-5d",chart[point[0]][stops[0]]+chart[stops[0]][stops[1]]+chart[point[1]][stops[1]]);
                      }
                 
                      else if(numstops==3)
                      {
                      printf("\n Starting from %s To %s is %d miles",pos[0],stopname[0],chart[point[0]][stops[0]]);
                      printf("\n From %s To %s is %d miles",stopname[0],stopname[1],chart[stops[0]][stops[1]]);
                      printf("\n From %s To %s is %d miles",stopname[1],stopname[2],chart[stops[1]][stops[2]]);
                      printf("\n From %s To %s is %d miles",stopname[2],pos[1],chart[point[1]][stops[2]]);
                      printf("\n Total Distance : %-5d",chart[point[0]][stops[0]]+chart[stops[0]][stops[1]]+chart[stops[1]][stops[2]+chart[point[1]][stops[2]]);
                      }
 
              } 
             
              else if(numstops==0)
              {
                printf("\n From %s To %s is %d miles",pos[0],pos[1],chart[point[0]][point[1]]);   
                printf("\n Total distance  : %-5d miles", chart[point[0]][point[0]]+chart[point[0]][point[1]]); // Adds the 2 points togteher to work out the distance
                }
               
            printf("\n\n\n");
                        main();        //  calls the menu method once finshed
                        break;
                       

    case 3:
            printf(" 1: London\n 2: Bath\n 3: Cardiff\n 4: Carlisle\n 5: Durham\n 6: Exeter\n 7: Leeds\n 8: Norwich\n 9: Truro\n 0: York\n -------------------\n\n");         
            for(i=0;i<2;i++)
            {
              if(i==0){printf("\n Please enter your Start point: ");} // input first point
              if(i==1){printf("\n Please enter your Finishing point: ");} // input first point       
              scanf("%s", &pos[i]);
                    if( strcmp( pos[i], "London" ) == 0 ){point[i]=0;}
            else if( strcmp( pos[i], "Bath" ) == 0 ){point[i]=1;}
            else if( strcmp( pos[i], "Cardiff" ) == 0 ){point[i]=2;}
            else if( strcmp( pos[i], "Carlisle" ) == 0 ){point[i]=3;}
            else if( strcmp( pos[i], "Durham" ) == 0 ){point[i]=4;}
            else if( strcmp( pos[i], "Exeter" ) == 0 ){point[i]=5;}
            else if( strcmp( pos[i], "Leeds" ) == 0 ){point[i]=6;}
            else if( strcmp( pos[i], "Norwich" ) == 0 ){point[i]=7;}
            else if( strcmp( pos[i], "Truro" ) == 0 ){point[i]=8;}
            else if( strcmp( pos[i], "York" ) == 0 ){point[i]=9;}
            else{printf("\n Invalid place please Re enter: ");i--;}
            }
           
                                  if(chart[point[0]][point[0]]+chart[point[0]][point[1]] <=100)
                                {
                                printf("\n Your Journey is less than 100 miles, Price per mile = 0.40");
                        printf("\n The price of your journey is : %5lf", chart[point[0]][point[0]]+chart[point[0]][point[1]]*0.4); // Adds the 2 points togteher and multiplys by 0.4 to get the ppm
                    printf("\n\n\n");
                }
                  else if(chart[point[0]][point[0]]+chart[point[0]][point[1]] >100)
                  {
                    printf("\n Your Journey is over 100 miles, Price per mile = 0.30");
                        printf("\n The price of your journey is : %5lf", chart[point[0]][point[0]]+chart[point[0]][point[1]]*0.3); // Adds the 2 points togteher and multiplys by 0.4 to get the ppm
                    printf("\n\n\n");
                  }
             
                        main();        //  calls the menu method once finshed
                        break;


    case 4: printf("\n Thankyou and goodbye"); //exits the program
            break;       
       
    }
}

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Quote:

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i still havent got it to import from text file

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What DOES it do?

Quote:

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Originally Posted by vart

What DOES it do?

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what the program its for a school assignment it works out distances between places the distances are not correct buttt the program needs to have

Code:

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  char chart1[11][11][11] ={ // Array for the Table and Plot points
  "-", "London", "Bath", "Cardiff", "Carlisle", "Durham", "Exeter", "Leeds", "Norwich", "Truno", "York",
  "London", "-", "23", "12", "89", "456", "123", "46", "732", "345", "123",
  "Bath", "23", "-", "46", "234", "123", "46", "89", "234", "567", "90",
  "Cardiff", "12", "46", "-", "767", "456", "46", "234", "123", "732", "35",
  "Carlisle", "89", "234", "767", "-", "732", "32", "48", "67", "98", "100",
  "Durham", "456", "123", "456", "732", "-", "234", "46", "89", "89", "732",
  "Exeter", "123", "46", "46", "32", "234", "-", "123", "46", "123","234",
  "Leeds", "46", "89", "234", "48", "46", "123", "-", "46", "89", "19",
  "Norwich", "732", "234", "123", "67", "89", "46", "46", "-", "123", "732",
  "Truro", "345", "567", "732", "98", "89", "123", "89", "123", "-", "78",
  "York", "123", "90", "35", "100", "732", "234", "19", "732", "78", "-"};

---

that array^^^^ in a text file and then importated and stored in a string array but well the program needs loads more work done on it

I take it those "distances" are not actually the true distances, just typed in "random" numbers - sorry, I thought they actually were "correct" distances.

--
Mats

hahah naaa there not im just stuck on how to get the data from text file into the arrayany suggestions on how this can be done....... then i have whats needed for the requirements then i can improve on the program

i have this : data.txt

Code:

---

-        London        Bath        Cardiff        Carlisle        Durham        Exeter        Leeds        Norwich        Truro        York
London        0        23        12        89        456        123        46        732        345        123
Bath        23        0        46        234        123        46        89        234        567        90
Cardiff        12        46        0        767        456        46        234        123        732        35
Carlisle        89        234        767        0        732        32        48        67        98        100
Durham        456        123        456        732        0        234        46        89        89        732
Exeter        123        46        46        32        234        0        123        46        123        234
Leeds        46        89        234        48        46        123        0        46        89        19
Norwich        732        234        123        67        89        46        46        0        123        732
Truro        345        567        732        98        89        123        89        123        0        78
York        123        90        35        100        732        234        19        732        78        0

---

and well i can read this data and store in a string fyne using

Code:

---

char chart1[11][11][16];
  FILE *infile;
    infile = fopen("data.txt", "r");      // using relative path name of file
              if (infile == NULL)
            {
            printf("Unable to open file.");
            }
            for(row=0; row<11;row++) // reads in the data into the array in 2 loops
              {                   
                      for(col=0;col<11;col++)
                      {
                        fscanf(infile,"&#37;s", chart1[row][col]);
                      }
                   
              }

---

and well i want to read just the numbers into an int array so i can work with them sooooo the array once the data has gone into the array it will be like this soo [0][1] when printed out will print out 23

Code:

---

0        23        12        89        456        123        46        732        345        123
23        0        46        234        123        46        89        234        567        90
12        46        0        767        456        46        234        123        732        35
89        234        767        0        732        32        48        67        98        100
456        123        456        732        0        234        46        89        89        732
123        46        46        32        234        0        123        46        123        234
46        89        234        48        46        123        0        46        89        19
732        234        123        67        89        46        46        0        123        732
345        567        732        98        89        123        89        123        0        78
123        90        35        100        732        234        19        732        78        0

---

sooo i can then work with these numbers can anyone show me how i can do this

so now when you have all the text read
use something like strtol to convert chart1[i][j] into chart2[i-1][j-1]

Code:

---

for(i=1;i<11;i++)
  for(j=1;j<11;j++)

---

where chart2 is declared as
long chart2[10][10];

Quote:

---

Originally Posted by vart

so now when you have all the text read
use something like strtol to convert chart1[i][j] into chart2[i-1][j-1]

Code:

---

for(i=1;i<11;i++)
  for(j=1;j<11;j++)

---

where chart2 is declared as
long chart2[10][10];

---

im confussed lol my chart i work with is a int chart and i dont know anything about strtol

This might just be confusing, but one alternative to this

Code:

---

            if( strcmp( pos[i], "London" ) == 0 ){point[i]=0;}
            else if( strcmp( pos[i], "Bath" ) == 0 ){point[i]=1;}
            /* ... */
            else{printf("\n Invalid place please Re enter: ");i--;}

---

is this:

Code:

---

const char *cities[] = {
    "London", "Bath", /* ... */
};
size_t x;

for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++) {
    if(!strcmp(cities[x], pos[i])) {
        point[i] = x;
    }
}

---

Of course, since the cities are in alphabetical order, you could do a binary search on them, but let's not get into that . . . . Wrapping that into a function would be a good idea, too.

I'm not sure how much your code has changed, but post #85's code has an error here:

Code:

---

chart[stops[1]][stops[2] +

---

(A missing ].)

Code:

---

if (choice < 1 | choice > 4)

---

->

Code:

---

if (choice < 1 || choice > 4)

---

Code:

---

scanf("%s", &pos[i]);

---

->

Code:

---

scanf("%s", pos[i]);

---

A return 0; wouldn't hurt, either.

Then it seems to be working for me . . . .

Code:

---

Please enter your Start point: London

 Please enter your Finishing point: Truro

 Please Enter the number of stops 0-3: 3

 Please enter the name for Stop 1: Durham

 Please enter the name for Stop 2: Leeds

 Please enter the name for Stop 3: York

 Starting from London To Durham is 456 miles
 From Durham To Leeds is 46 miles
 From Leeds To York is 19 miles
 From York To Truro is 78 miles
 Total Distance : 599

---

Of course, that's with the static array chart.

Now, how to convert chart1[] into chart[]? One way, if you don't like strtol(), is to use sscanf(). Has this been mentioned already? I haven't read the whole thread . . . .

And you'll also have to load chart1[] from a file. I suggest fopen(), fgets(), strtok(), and fclose().

Or combine the two steps and use fopen(), fscanf(), and fclose(). It's less robust, but easier.

For example:

Code:

---

int x, y;

for(y = 0; y < 10; y ++) {
    fscanf(fp, "%s", cityname[y]);
}

for(y = 0; y < 10; y ++) {
    fscanf(fp, "%s", unusedname);
    for(x = 0; x < 10; x ++) {
        fscanf(fp, "%i", &chart[y][x]);
    }
}

---

Something like that might get you started . . . .

lol im still conussed on what this code u throw at me is ment to do

how ever i have fixed the problems its just getting that bloddy array into an int array

Code:

---

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>

#define CITIES 10

/* Structure holding the name and the distance. */

typedef struct _Distance
{
        char *CityTo;
        int dist;
}Distance;

/* Structure holding the name of the city and the distances from all other cities. */

typedef struct _CityDistance
{
        char *CityFrom;
        Distance *Cities;
}CityDistance;

/* Read the contents from the file. */

CityDistance *ReadContents(const char *filename)
{
        if(!filename)
        {
                fprintf(stderr, "Error NULL filename pointer.\n");
                return NULL;
        }
        else
        {
                /* Pointer to a file. */
                FILE *fileptr = NULL;
                /* Pointer to a CityDistance struct. */
                CityDistance *CDist = NULL;
                /* Index to Cities. */
                static int Index = 0;
                /* Iteration. */
                int FirstIteration = 0;
                int nError = 0;
                /* Avoid Write. */
                int AvoidWriteIndex = 0;
                /* City Index. */
                int CityIndex = 0, CityIndex1 = 0;
                /* Buffer to hold the line. */
                char LineBuffer[BUFSIZ] = "";
                /* Pointer for strtok. */
                char *token = NULL;
                /* Try to open the file first. */
                if((fileptr = fopen(filename, "rt")) == NULL)
                {
                        fprintf(stderr, "Error in opening <&#37;s> filename.\n", filename);
                        return NULL;
                }
                /* Try to alloc memory. */
                if((CDist = calloc(CITIES, sizeof(CityDistance))) == NULL)
                {
                        fprintf(stderr, "Error in memory.\n");
                        fclose(fileptr);
                        return NULL;
                }
                for(Index = 0; Index < CITIES; Index++)
                {
                        if((CDist[Index].Cities = calloc(CITIES-1, sizeof(Distance))) == NULL)
                                for(; Index >= 0; Index--)
                                {
                                        free(CDist[Index].Cities);
                                        CDist[Index].Cities = NULL;
                                }
                }
                if(!Index)
                {
                        free(CDist); CDist = NULL;
                        fclose(fileptr);
                        return NULL;
                }
                /* Set Index Back to zero. */
                Index = 0;
                /* Read from file. */
                while((fgets(LineBuffer, sizeof(LineBuffer), fileptr)) != NULL && Index < CITIES)
                {
                        /* Trim the pending '\n' in the end due to fgets(). */
                        if(LineBuffer[strlen(LineBuffer)-1] == '\n')
                                LineBuffer[strlen(LineBuffer)-1] = '\0';
                        /* Did we read something. */
                        if(LineBuffer[0] == '\0')
                                break;
                        /* Use strtok. */
                        token = strtok(LineBuffer, " ");
                        if(!FirstIteration && token)
                        {
                                while(token != NULL && Index < CITIES)
                                {
                                        CDist[Index++].CityFrom = strdup(token);
                                        token = strtok(NULL, " ");
                                }
                                /* Init CitiesTo. */
                                for(Index = 0; Index < CITIES; Index++)
                                {
                                        while(CityIndex < CITIES)
                                        {
                                                if(CityIndex != Index)
                                                        CDist[Index].Cities[CityIndex1++].CityTo = strdup(CDist[CityIndex].CityFrom);
                                                CityIndex++;
                                        }
                                        CityIndex1 = 0;
                                        CityIndex = 0;
                                }
                                /* Reset Counters. */
                                Index = 0, CityIndex = 0;
                                /* Ensure we will not enter. */
                                FirstIteration = 1;
                        }
                        if(FirstIteration && token && nError)
                        {
                                while(token != NULL)
                                {
                                        if(!strcmp(token, "-") || !strcmp(token, CDist[Index].CityFrom))
                                        {
                                                token = strtok(NULL, " ");
                                                continue;
                                        }
                                        CDist[Index].Cities[CityIndex++].dist = atoi(token);
                                        token = strtok(NULL, " ");
                                }
                        }

                        /* In any case. */
                        if(nError)
                                Index++;
                        nError = 1;
                        CityIndex = 0;
                        memset(LineBuffer, 0 , sizeof(LineBuffer));
                }
                        fclose(fileptr);
                return CDist;
        }
}
/* Print the results. */

void PrintCitiesAndDistances(const CityDistance *cities)
{
        int CityIndex = 0, DistanceIndex = 0;
        for(CityIndex = 0; CityIndex < CITIES; CityIndex++)
        {
                printf("\nPrinting Distances from:%s\n\n", cities[CityIndex].CityFrom);
                while(DistanceIndex < CITIES-1)
                {
                                printf("From:%s---->To:%s = %d\n", cities[CityIndex].CityFrom, cities[CityIndex].Cities[DistanceIndex].CityTo, cities[CityIndex].Cities[DistanceIndex].dist);
                                DistanceIndex++;
                }
                DistanceIndex = 0;
        }
        printf("\n\n");
}

/* Main Code. */
int main(int argc, char *argv[])
{
        int i;
        CityDistance *n = NULL;
        n = ReadContents("cities.txt");
        PrintCitiesAndDistances(n);
        printf("Hit enter to continue...");
        getchar();
}

---

Bokarinho....

It's really excellent that you have his homework so well planned out, Bokarinho. You should be getting paid for this.

A much more elegant solution exists using parallel arrays, by the way.

it doesnt help geeting taught the very basics very badly and well alot of code u guys give me confusses me haha but i shall give it a shot

I have the same Assignment,
im stuck at the point where we have to read in a .txt file of numbers and put them into a 2d array.

The code im using for opening the file, and putting the numbers into a 2d array is:

Code:

---

FILE *file;
 int a = 0, b = 0;
 int table[a][b];
 file = fopen("numbers2.txt", "r");

---

Code:

---

if(file != NULL) // file exists
  {
   
    printf("File opened successfully.\n");
     
      for (a=0; a <= col;a++)
        {
          for (b=0; b <= row;b++)
          {
          fscanf(file, "&#37;d ", &table[a][b]);
           

            printf("%-4d ", table[a][b]);
          }
          printf("\n");
        }
     
      fclose(file);                 
  }
    else // file doesn't exist
 {
  printf("Error: can't open file\n");
 }

---

in my program I have a switch statement for the different options, 1 of the options is to display the numbers:

Code:

---

File opened successfully.
0    23  12  89  456  123  46  732  345  123
23  0    46  234  123  46  89  234  567  90
12  46  0    767  456  46  234  123  732  35
89  234  767  0    732  32  48  67  98  100
456  123  456  732  0    234  46  89  89  732
123  46  46  32  234  0    123  46  123  234
46  89  234  48  46  123  0    46  89  19
732  234  123  67  89  46  46  0    123  732
345  567  732  98  89  123  89  123  0    78
123  90  35  100  732  234  19  732  78  0

---

Then the first option in the program is to enter 2 numbers,

Quote:

---

printf("Enter 2 Numbers: ");
Distance = (table[num1][num2]);
printf("%-4d", table[num1][num2]);
printf(" Miles");
printf("\n");

---

So it should be reading from the 2d array, the problem is that it seems to be only reading the very bottom row and doesn't read the columns at all:

Code:

---

------------------------------
Please enter your choice:
------------------------------
1
Enter 2 Numbers: 2
2
35  Miles

------------------------------

---

So I think that it isn't actually inserting the numbers in the txt file into a 2d array?
Any help would be appreciated.

printf("Enter 2 Numbers: ");
Distance = (table[num1][num2]);

Shouldn't you have some input between these two lines?

So at the moment it's just reading 1 of the numbers input? or assigning the same number to both num1 and num2?. How do I fix this?

at the moment it is using the same values of the num1,num2 vars that are left from the previous calculations.

if you asking to enter 2 numbers use some input function to read them - for example scanf

Code:

---

if(scanf("%d%d", &num1, &num2) == 2)
{
  /* use the input */
}
else
{
  /* clear the stdin and try again */
}

---

Quote:

---

So at the moment it's just reading 1 of the numbers input? or assigning the same number to both num1 and num2?. How do I fix this?

---

By using scanf() or some such. What you have now never looks at what the user enters. You need something like this:

Code:

---

printf("Enter 2 Numbers: ");
scanf("%d%d", &num1, &num2);
Distance = (table[num1][num2]);

---

(Once you understand that, check vart's more robust example.)

Quote:

---

Originally Posted by dwks

By using scanf() or some such. What you have now never looks at what the user enters. You need something like this:

Code:

---

printf("Enter 2 Numbers: ");
scanf("%d%d", &num1, &num2);
Distance = (table[num1][num2]);

---

(Once you understand that, check vart's more robust example.)

---

Ok, I tried this, and it prints this:

Quote:

---

------------------------------
Please enter your choice:
------------------------------
1
Enter 2 Numbers: 3
3
4199093 Miles

------------------------------

---

I don't know where it's getting that number from :s

so try to extend your printf

Code:

---

printf("[%d][%d] = %-4d", num1, num2, table[num1][num2]);

---

OK done that:

Quote:

---

------------------------------
Please enter your choice:
------------------------------
1
Enter 2 Numbers: 6
5
[6][5] = 2009252579 Miles

------------------------------

---

I don't know where it's getting the 2009252579 number from :s
I guess it's not putting the numbers from the txt file into a 2d array correctly.

It should return 234 Miles.

This is the code I have for opening the txt file, scanning it and putting it into an array:

Code:

---

if(file != NULL) // file exists
  {
   
    printf("File opened successfully.\n");
     
      for (a=0; a <= col;a++)
        {
          for (b=0; b <= row;b++)
          {
          fscanf(file, "%d ", &table[a][b]);
           

            printf("%-4d ", table[a][b]);
          }
          printf("\n");
        }
     
      fclose(file);                 
  }
    else // file doesn't exist
 {

---

It should be putting the numbers from the txt file into a 2d Array, I guess it's not?, and if it's not, hope do I get it to work correctly.

There are a few things wrong with that.

First of all, your file consists of strings (names) as well as numbers, does it not? What do you think will happen when fscanf() is told to find a number and it sees a string? It returns without reading the string and without setting its numerical argument to anything. In other words, if this happened, table[a][b] would not be initialized, which is exactly what looks like is happening.

What can you do about this? Well, you can see if it's happening with this:

Code:

---

if(fscanf(file, "%d ", &table[a][b]) != 1) {
    printf("Error reading table[%d][%d]\n", a, b);
}

---

And you can "fix" it with this:

Code:

---

while(fscanf(file, "%d ", &table[a][b]) != 1) {
    int c;
    do {
        c = getc(file);
    } while(c != '\n');
}

---

(Note that that doesn't handle EOF, but it's good enough for now.)

When fscanf() encounters something it didn't like, that code removes any characters up until a newline and then tries the fscanf() call again.

Of course, that doesn't fix the real problem: you're probably interested in the names, after all. So instead of just discarding them, why don't you have another look at the code that I threw at you?

Code:

---

int x, y;

for(y = 0; y < 10; y ++) {
    fscanf(fp, "%s", cityname[y]);
}

for(y = 0; y < 10; y ++) {
    fscanf(fp, "%s", unusedname);
    for(x = 0; x < 10; x ++) {
        fscanf(fp, "%i", &chart[y][x]);
    }
}

---

Your input file consists of ten names, followed by ten lines with a name and ten numbers on them. That's exactly what this code reads. It discards the name on the last ten lines, because that same information can be obtained from the first line.

Please, examine that and tell me what you don't understand about it . . . . :)

Also -- I think your loops are looping too often.

Code:

---

      for (a=0; a <= col;a++)
        {
          for (b=0; b <= row;b++)

---

Most of the time, you'll want < instead of <= in loops like those.

does the table you fill and table you print member later is the same array?

or these parts of the code are in different functions?

Here's the code at the moment:

Code:

---

#include <stdio.h>
#include <math.h>
#define col 9
#define row 9

// Menu
char menu(void);

int main(void)
{
  // file opening stuff 
 FILE *file;
 int a = 0, b = 0;
 int table[a][b];
 file = fopen("numbers2.txt", "r"); 

  char option,rtn;
  int i, j;
  int Distance = 0;
  double Cost = 0.0;

  option = menu();
  while(option != '5')
  {
  switch(option)
  {     
      case '1': 
{
                // works out distance between 2 points the user enters
                printf("Enter 2 Numbers: ");
                scanf("&#37;d%c", &a, &rtn);
                scanf("%d%c", &b, &rtn);
                Distance = (table[a][b]);
                printf("%-4d", table[a][b]);
                printf(" Miles");
                printf("\n");
}
                  break;
                 
        case '2' :
 {       
                // calculates cost of journey
                Cost = (Distance * 0.40);
                printf("Cost: &#163;");
                printf("%2.2f", Cost);
                printf("\n");
}
        break;         
                 
                 
          case '3':
{
   
if(file != NULL) // file exists
  {
   
    printf("File opened successfully.\n");
     
      for (a=0; a <= col;a++)
        {
          for (b=0; b <= row;b++)
          {
          fscanf(file, "%d ", &table[a][b]);
           

            printf("%-4d ", table[a][b]);
          }
          printf("\n");
         
        }
     
      fclose(file);
                       
  }
    else // file doesn't exist
 {
  printf("Error: can't open file\n");
 }
}           
                  break;
                 
                      case '4': 
{

                printf("%-4d", table[10][3]);

}
                  break;
                   
  default:
         
  printf("\n-----------------------------\n");
  printf("Invalid choice.\n");
  printf("-----------------------------\n");
 
    }
    option = menu();
  }
}   

        char menu(void)
{
       
// Print Main Menu 
       
  char option,rtn;
  printf("\n------------------------------\n");
  printf("            Menu                ");
  printf("\n------------------------------\n");
  printf("1 - Enter 2 Points\n");
  printf("2 - Calculate Cost of Journey\n");
  printf("3 - Display Table\n");
  printf("4 - Test\n");
  printf("5 - Quit");
  printf("\n------------------------------\n");
  printf("Please enter your choice: ");
  printf("\n------------------------------\n");
  scanf("%c%c",&option,&rtn);
  return option;
}

---

numbers2.txt (NOTE: im not using the place names at the moment, but I will get on to that after I have got this to work)

Code:

---

0 23 12 89 456 123 46 732 345 123
23 0 46 234 123 46 89 234 567 90
12 46 0 767 456 46 234 123 732 35
89 234 767 0 732 32 48 67 98 100
456 123 456 732 0 234 46 89 89 732
123 46 46 32 234 0 123 46 123 234
46 89 234 48 46 123 0 46 89 19
732 234 123 67 89 46 46 0 123 732
345 567 732 98 89 123 89 123 0 78
123 90 35 100 732 234 19 732 78 0

---

the number for A doesn't work, it just ignores the number input for A
Input for b works, it goes to the right number, but on the last line :s

[CODE]
------------------------------
Please enter your choice:
------------------------------
1
Enter 2 Numbers: 4
3
98 Miles

------------------------------
[CODE]
The first number isn't being counted, but the 2nd one is :s.

Any help please :)

Quote:

---

int a = 0, b = 0;
int table[a][b];

---

so you define table of zero size, how do you plan to read something into it? Make some room buddy!!

Ok, right I think I might have got this working, I changed the 0's to 9's. When I go to the option to enter in 2 numbers I get

Code:

---

------------------------------
Please enter your choice:
------------------------------
1
Enter 2 Numbers: 1
1
1160589875 Miles

---

But, if I enter 3 at the menu to bring up the table, and then it goes back to the menu and I choose the enter 2 numbers option again, it's correct:

Code:

---

------------------------------
Please enter your choice:
------------------------------
1
Enter 2 Numbers: 1
1
0    Miles

------------------------------

---

So I guess that I should have the program load both the table and the menu.
But I just want the table to show once under the menu. Then when I go back to the main menu for the other options it won't show the table anymore, but it will still be loaded, if that makes any sense :S

printf("&#37;-4d", table[10][3]); - what does this suppose to do?

you already have a code the correctly scans all the table - use it

Code:

---

for (a=0; a <= col;a++)
{
        for (b=0; b <= row;b++)
        {
                printf("%-4d ", table[a][b]);
        }
        printf("\n");
}

---

death yea thats how the first program was i have data.txt

Code:

---

-        London        Bath        Cardiff        Carlisle        Durham        Exeter        Leeds        Norwich        Truro        York
London        0        23        12        89        456        123        46        732        345        123
Bath        23        0        46        234        123        46        89        234        567        90
Cardiff        12        46        0        767        456        46        234        123        732        35
Carlisle        89        234        767        0        732        32        48        67        98        100
Durham        456        123        456        732        0        234        46        89        89        732
Exeter        123        46        46        32        234        0        123        46        123        234
Leeds        46        89        234        48        46        123        0        46        89        19
Norwich        732        234        123        67        89        46        46        0        123        732
Truro        345        567        732        98        89        123        89        123        0        78
York        123        90        35        100        732        234        19        732        78        0

---

i want to extract all the numbers from it into an array without having it statically set like this:

Code:

---

int chart [10][10] = { // Array for the Table and Plot points
  {0,23,12,89,456,123,46,732,345,123},
  {23,0,46,234,123,46,89,234,567,90},
  {12,46,0,767,456,46,234,123,732,35},
  {89,234,767,0,732,32,48,67,98,100},
  {456,123,456,732,0,234,46,89,89,732},
  {123,46,46,32,234,0,123,46,123,234},
  {46,89,234,48,46,123,0,46,89,19},
  {732,234,123,67,89,46,46,0,123,732},
  {345,567,732,98,89,123,89,123,0,78},
  {123,90,35,100,732,234,19,732,78}
    };

---

i want to take that same above data from the text file without the place names and the -

right after quite a bit of reading and playing i have got it however i have got a out put issue which i dont under stand.

this is my text file data.txt

Code:

---

-        London        Glasgow        Birmingham        Manchester        Luton        Derby        Bournemouth        Stafford        Stoke        Cardiff                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
0        403        118        209        34        129        108        141        158        151        403        0        209        217        371        285        455        263        249        398        118        209        0        96        86        46        170        28        44        124        209        217        96        0        176        90        261        68        54        203        34        371        86        176        0        97        122        109        126        166        129        285        46        90        97        0        199        34        36        162        108        455        170        261        122        199        0        194        210        164        141        263        28        68        109        34        194        0        16        137        158        249        44        54        126        36        210        16        0        153        151        398        124        203        166        162        164        137        153        0

---

notice ive changed the data all the distances are correct

right this is my test program to read in from a text file and outputto scree:

Code:

---

#include <stdio.h>
#include <stdlib.h>

void readin(char towns[11][11], int dist[10][10]);
void display(char towns[11][11], int dist[10][10]);

int main (void)
{
    char towns[11][11];
    int dist[10][10];
    int choice;
    readin(towns,dist);
    display(towns,dist);
    printf("continue?");
    scanf("%d",&choice);
}






void readin(char towns[11][11], int dist[10][10])
{
    int i, j;
        char filename[21], p1, p2;
        FILE *in_file;

        printf("\nEnter the name of the input file, name must be 20 charecters or less: ");
        scanf("%s", &filename);
       
        //open the file and read from it

       
        in_file = fopen(filename,"r");

        if (in_file == NULL)
        {
                printf("\nCannot open %s\n", &filename);
        }
    else if (in_file != NULL)
    {
        for(i=0;i<11;i++)
        {
                fscanf(in_file, "%s ", &towns[i]);
        }

        for(i=0;i<10;i++)
        {
                for(j=0;j<10;j++)
                {               
                        fscanf(in_file, "%d ", &dist[i][j]);
                }
        }
}

}

void display(char towns[11][11], int dist[10][10])
{
        int row, col;
        printf("\n------------------------------------------Distance Chart--------------------------------------------------\n");
       
        for (row=0; row<11;row++)
        {
            printf("%-14s",towns[row]);
        }
        printf("\n");
        for (row=0; row<10;row++)
        {
            printf("%-14s",towns[row+1]);
           
                for (col=0;col<10;col++)
                printf("%-14d", dist[row][col]);
                printf("\n");
        }     
        printf("\n----------------------------------------------------------------------------------------------------------\n");
}

---

everything seems to be ok but when i go to run it i get this output:

http://i57.photobucket.com/albums/g2...k/output-1.jpg


i dont see more than 1 stafford in my txt file why is this happening and how can i fix it

probably due to a buffer overrun. You only allow the storage of 11 characters for each town name, but Bournemouth requries 12. 11 plus a null character.

Since there is no null stored at the end of Bournemouth, when you print it, it prints until a null is encountered.

Oh my goodness!
Don't read strings with scanf in such a unsafe way.
Have a read: http://cpwiki.sf.net/Buffer_overruns

ive fixed it a place name was tooo long so i changed it

Fix your scanf and fscanf. Read the article I linked to.
Great article and it really shows the horrors of buffer overruns (which is exactly what your code is prone to!).

Quote:

---

Originally Posted by Elysia

Fix your scanf and fscanf. Read the article I linked to.
Great article and it really shows the horrors of buffer overruns (which is exactly what your code is prone to!).

---

gonna fix that when my program is fabb




new problem

i have this code i want it to recognise when i have enterd a incorrect place name

Code:

---


const char *cities[] = {"London", "Glasgow", "Birmingham",        "Manchester", "Luton", "Poole", "Stafford", "Stoke", "Cardiff", "Derby"};

    else if(numstops>0)
              {
               
                  for(i=0;i<numstops;i++) //loops round depeneding on how many stops was enterd
                  {
                    if(wrong !=1)
                    {                   
                    printf("\n Please enter the name for Stop %-1d: ",i+1);
                    }
                  wrong=0; 
                  scanf("%16s",stopname[i]);
                          size_t x;
                          for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++)
                          {
                              if(!strcmp(cities[x], stopname[i])) {stops[i] = x;} // assigns stops a number depends what place name was enterd
                            }
                              if(stops[i]>9 || stops[i]<0)
                              {
                              printf("\n Invalid place name please re enter: ");
                              i--;
                              wrong=1;           
                              }
                  }

---

i get thisss

http://s57.photobucket.com/albums/g2...ent=hmmmmm.jpg

im trying to get the program to output a error messege when a invalid place name is put in and ask for re input of the name i just cant get it to go

You badly need to work on that indentation.

Code:

---

const char *cities[] = {"London", "Glasgow", "Birmingham",        "Manchester", "Luton", "Poole", "Stafford", "Stoke", "Cardiff", "Derby"};

        else if(numstops>0)
        {

                for(i=0;i<numstops;i++) //loops round depeneding on how many stops was enterd
                {
                        if(wrong !=1)
                        {                   
                                printf("\n Please enter the name for Stop %-1d: ",i+1);
                        }
                        wrong=0; 
                        scanf("%16s",stopname[i]);
                        size_t x;
                        for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++)
                        {
                                if(!strcmp(cities[x], stopname[i])) {stops[i] = x;} // assigns stops a number depends what place name was enterd
                        }
                        if(stops[i]>9 || stops[i]<0)
                        {
                                printf("\n Invalid place name please re enter: ");
                                i--;
                                wrong=1;           
                        }
                }

---

You're missing a lot of braces (and code, too, I would bet).

Quote:

---

Originally Posted by Elysia

You badly need to work on that indentation.

Code:

---

const char *cities[] = {"London", "Glasgow", "Birmingham",        "Manchester", "Luton", "Poole", "Stafford", "Stoke", "Cardiff", "Derby"};

        else if(numstops>0)
        {

                for(i=0;i<numstops;i++) //loops round depeneding on how many stops was enterd
                {
                        if(wrong !=1)
                        {                   
                                printf("\n Please enter the name for Stop %-1d: ",i+1);
                        }
                        wrong=0; 
                        scanf("%16s",stopname[i]);
                        size_t x;
                        for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++)
                        {
                                if(!strcmp(cities[x], stopname[i])) {stops[i] = x;} // assigns stops a number depends what place name was enterd
                        }
                        if(stops[i]>9 || stops[i]<0)
                        {
                                printf("\n Invalid place name please re enter: ");
                                i--;
                                wrong=1;           
                        }
                }

---

You're missing a lot of braces (and code, too, I would bet).

---

yeaaaaaaaaaaa i know my code is not the best at setting out but welll i leave things like that to the end
i just dont know how to get to check the input place name and well if its not in the struct ask for re inputt

anyone know how i can make it soooo if i was to put in france it would check and say sorry invalid place name please re enter i have been trying for ages and still cant get it to work

right this is the code im stuck on

Code:

---

  char pos[2][16];
    const char *cities[] = {"London", "Glasgow", "Birmingham",        "Manchester", "Luton", "Poole", "Stafford", "Stoke", "Cardiff", "Derby"};

    scanf("%15s", pos[i]);
                          size_t x; 
                          for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++) {
                          if(!strcmp(cities[x], pos[i])){point[i] = x;}
                          }

---

The user will input a place name saved in pos and if pos is equal to cities which contains = "London", "Glasgow", "Birmingham","Manchester", "Luton", "Poole", "Stafford", "Stoke", "Cardiff", "Derby" ..... i want it to to put out a error message and ask for re input of the place sooo if i was to enter France it would check cities find out its not there and ask for re input can anyone help

thankyou

Eh? You want it to print an error if the user enters a city such as London that exists within the array or only if they enter one that isn't in the array?

Quote:

---

Originally Posted by Elysia

Eh? You want it to print an error if the user enters a city such as London that exists within the array or only if they enter one that isn't in the array?

---

yess if it doesnt exist in the array i want a print error ( soz i was sleepy when i wrote that bad english ol )

What you can do is use a flag, a bool, and initialize it to false.
Then loop through your array and check if you can find a string that matches what the user inputted.
If you find one, set flag to true and break the loop.
That way you know that if the flag is false, no match was found, and if it's true, then the city was found.

hmmm im a little confused about how i would implement this

Start with what you can. Take it one step at a time.

atm im messing around with this idea

Code:

---

    scanf("%16s", pos[i]);
                          size_t x; 
                          for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++) {
                          if(!strcmp(cities[x], pos[i])==0){point[i] = x;}
                          else if (!strcmp (cities[x],pos[i])!=0)
                            {
                              flag++;
                            }
                          }
                          while(flag==10)
                          {
                            printf("Invalid place name please re enter: ");
                            wrong=1;
                            i++;     
                          }

---

Code:

---

flag found = false;
for every element in the array
{
    if (input is the same as array at position i) then
    {
        set flag to true;
        break out of loop;
    }
}
if flag is false, the string was not found in the array.

---

Pseudo.

Thread has a 129 posts and it appears that the OP has made little progress.

Surely, someone can post a basic input validation function consisting of about 12 lines of code to help this guy out

And how exactly will that help?

Well, the last 130 posts didn't help him much with a basic homework assignment, an assignment that would only take approximately 80 lines of code to write. Maybe it's time to spoon feed him actual code.

And what will this accomplish? You're just handing code over to someone. Then they'll make the same thing over and over and come back for help.
It's pretty much the same as handing over some code just to make someone pass their test. In other words, cheating. They won't get anywhere.

The only thing it'll accomplish is to bring an end to this long drawn out thread a lot sooner. I would strongly encourage the OP to discuss his/her homework assignment with his/her instructor for additional guidance and direction since it's apparent he/she is not making much progress on a very basic homework assignment.

Absolutely. I concur. But handing out the solution is not ideal (note that I'm not implying that are you suggesting this).

Fortune, perhaps it's time you tried to get some guidance from your instructor?

lol my instructer will say look at the lecture notes and well theres nothing on there bout what im stuck on lol i aint the best at C but its giving me headaches but im gonna try figure this out

right i have managed to get it to put out an error message but having problems with if its true setting the point for the places.

i decided to use flag as a int and set it to 1 or 0.

this is what i have

Code:

---

        wrong=0; 
                    scanf("%16s", pos[i]);
                          size_t x; 
                          flag = 0;
                          for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++)
                            {
                              if(!strcmp(cities[x], pos[i])==0){point[i] = x;} // assigns point a number depends what place name was enterd 
                              else {flag=1;}   
                            }
                            if(flag==0)
                            {
                              printf("\n Invalid place name please re enter: ");
                              i--;
                              wrong=1;     
                            }

---

output :
http://i57.photobucket.com/albums/g230/fortune2k/dd.jpg

You should get yourself a debugger. Perhaps Visual Studio.
And note that this line

Code:

---

if(!strcmp(cities[x], pos[i])==0){point[i] = x;}

---

Looks suspicious.
Strcmp returns 0 if the strings match. Yet the "!" operator inverses the result so if strcmp returns 1, it will be changed to 0 before the comparison. Likewise, if it returns 0 or < 0, it will be 1 before the compare. Watch out.

im using dev c++ maybe i should change sooo what shall i change it to then i tryed !=0 and taking it out completly and well it doesnt work

Code:

---

if(strcmp(cities[x], pos[i])==0){point[i] = x;}

---

Remove the "!".
Strcmp returns 0 if the strings are equal.
I suggest you get a debugger and learn basic debugging facilities. Stepping through code and checking the value of variables.
Basic stuff. There will come a day when you need a debugger.,

Quote:

---

Likewise, if it returns 0 or < 0, it will be 1

---

How is it so?

Code:

---

#include<stdio.h>
int main()
{
    printf("&#37;d %d %d\n", !(-1), !0 , !1);
    return 0;
}

---

output

Code:

---

0 1 0

---

That's what I get for not testing :rolleyes:
I assumed since < 0 will result in false, reversing the value will turn it "true."
Well, that goes to show that using ! can be dangerous if not used properly.

values that are < 0 as well as the values that are >0 all evaluate to true

ok uve confused me now

Quote:

---

Originally Posted by vart

values that are < 0 as well as the values that are >0 all evaluate to true

---

Brain error! :p
The area in the brain where the information was stored has been short circuited, so it fell back on trying to guess with the information it had which obviously turned out wrong! :p

Fortune: Don't use !strcmp, just do strcmp and compare to 0 to see if the strings match.

Quote:

---

Originally Posted by fortune2k

ok uve confused me now

---

What exactly?
in C:
0 - is false
all other values - are true

yes i understand that i mean how to have it set in the if statement

Quote:

---

Originally Posted by fortune2k

yes i understand that i mean how to have it set in the if statement

---

you do not need it here

Code:

---

if(strcmp(...) == 0)
{
  /* strings match */
}

---

or

Code:

---

if(strcmp(...) != 0)
{
  /* strings do not match */
}

---

depending on what you need

Quote:

---

Originally Posted by vart

you do not need it here

Code:

---

if(strcmp(...) == 0)
{
  /* strings match */
}

---

or

Code:

---

if(strcmp(...) != 0)
{
  /* strings do not match */
}

---

depending on what you need

---

right this is what i have

Code:

---

  scanf("%16s", pos[i]);
                          size_t x; 
                          flag = 0;
                          for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++)
                            {
                              if(!strcmp(cities[x], pos[i])==0){point[i] = x;} // assigns point a number depends what place name was enterd 
                              else if(!strcmp(cities[x], pos[i])!=0) {flag=1;}   
                            }
                            if(flag==0)
                            {
                              printf("\n Invalid place name please re enter: ");
                              i--;
                              wrong=1;     
                            }

---

i still get no distance output its still the same as

http://i57.photobucket.com/albums/g230/fortune2k/dd.jpg

You didn't change what they told you to change. Start there.

Quote:

---

Originally Posted by JDGATX

You didn't change what they told you to change. Start there.

---

ey ? what you mean

Code:

---

(!strcmp

---

get rid of the red

Quote:

---

Originally Posted by vart

Code:

---

(!strcmp

---

get rid of the red

---

yes i have done that and well i have been fiddling around n well now i am tottally confussed of wat sympols to use ect ect atm

Code:

---

    for(x = 0; x < sizeof(cities) / sizeof(*cities); x ++)
                            {
                              if(strcmp(cities[x], pos[i])){point[i] = x;} // assigns point a number depends what place name was enterd 
                              if(strcmp(cities[x], pos[i])) {flag=1;}   
                            }
                            if(flag==0)
                            {
                              printf("\n Invalid place name please re enter: ");
                              i--;
                              wrong=1;     
                            }

---

i have just that atm and just trying differnt symbols like ==0 ==1 >0 <0 ectect im just confussed

Go check the documentation for the return of strcmp. Don't guess!

all i could find is how to initialize strcmp and well the outcome

Code:

---


Negative if s1 is less than s2.
Zero if s1 and s2 are equal.
Positive if s1 is greater than s2

---

i still dont understand lol can anyone link me somthing so i can understand this stuff its been haunting me for a few days now

Quote:

---

Originally Posted by fortune2k

all i could find is how to initialize strcmp and well the outcome

Code:

---


Negative if s1 is less than s2.
Zero if s1 and s2 are equal.
Positive if s1 is greater than s2

---

i still dont understand lol can anyone link me somthing so i can understand this stuff its been haunting me for a few days now

---

yes http://cboard.cprogramming.com/showp...&postcount=148

Code:

---

Negative if s1 is less than s2.
Zero if s1 and s2 are equal.
Positive if s1 is greater than s2

---

What's the problem? I think both the doc and vart is clear. The answer has been handed to you several times.

Quote:

---

Originally Posted by vart

you do not need it here

Code:

---

if(strcmp(...) == 0)
{
  /* strings match */
}

---

or

Code:

---

if(strcmp(...) != 0)
{
  /* strings do not match */
}

---

depending on what you need

---

doesnt workkkk

Code:

---

if(strcmp(cities[x], pos[i])==0){point[i] = x;}
 if(strcmp(cities[x], pos[i])!=0) {flag=1;}

---

i get no error message no point output

Quote:

---

Originally Posted by fortune2k

doesnt workkkk

Code:

---

if(strcmp(cities[x], pos[i])==0){point[i] = x;}
 if(strcmp(cities[x], pos[i])!=0) {flag=1;}

---

i get no error message

---

So when you say "doesn't work" and "i get no error message", what do you expect to happen (that is the "works" I suppose), and how is that different when you say "doesn't work". The above is correct code for point[i] being set to x when pos[i] matches cities[x], and flag will be set to one if pos[i] is not equal to cities[x] - of course, if that's a direct copy of the code, I would prefer:

Code:

---

if(strcmp(cities[x], pos[i])==0)
 {
  point[i] = x;
 } else {
  flag=1;
 }

---

Edit: to clarify - if you have already tested that if the two strings are equal, comparing them again to see if they are "not equal" doesn't make much sense - we already know that. And strcmp() can be quite an expensive operation if the strings are nearly equal and long, so it's good practice to not do comparisons when they are not needed.

Edit2: Having read your code again, I think it looks like flag should be set to 1 when you have found the city, not the other way around. So perhaps what you really want is:

Code:

---

if(strcmp(cities[x], pos[i])==0)
 {
  point[i] = x;
  flag=1;
 }

---

Your code as it stands would always set flag = 1 at some point, because there's only at most one city name that matches, and all others will be a non-match - so you probably want set the flag ONLY when you have a match.
--
Mats

The code works, but the logic is all wrong. Think about what you're doing. When does flag need to be set? Perhaps you should rename it to something better, such as bNotFound or bFound or something like that.