Help

**dgibson2004** · 05-08-2006

Hi

I have a question that I could do with some help with.

1. Have got a college assignment to poduce a mileage chart.
I have to read 10 place names and a list of miles from a text file and enter it into a chart.

I have the following code I can get it to display the place names across the top and down the left hand column but I cannot get it to display the miles it just displays 0's.
I have tried changing the code and it seems to be looping throught to pick up the names from the text file, but not continuing to loop through and pick up the miles.

I have attached the code below and also the text file.

If there is anything obvious I have missed or missed out of the text file please let me know.

**********Code*****************

Code:

#include <stdio.h>
#include <string.h>

int menu(void);
void readFile(void);
void showchart(void);

int grid[10][10];

char names[10][5];

void showchart ()
{
int x, row, col;

FILE *in_file;
in_file = fopen("places.txt","r");

for (x=0;x<=9; x++)
{
fscanf(in_file, "%4c", names[x]);
}

printf("\n     ");

for (x=0; x<=9; x++)
{
printf("%6s",names[x]);
}

printf("\n");
for (row=0; row<=9; row++)
{
printf("%s", names[row]);
	for(col=0; col<=9; col++)
{
	fscanf(in_file, "%d", &grid[row][col]);
	printf("%6d", grid[row][col]);
}
printf("\n");
}
fclose(in_file);
}

***************end of code*************

The text file is as follows

***************text file****************

DealHullMullFordMuckButeIonaYorkWallSarkDeal
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
89
123
90
35
100
732
234
19
732
89
0

*********** End of Text File************

**dgibson2004** · 05-08-2006

This is what I am after

Hull Wall War Etc......

Hull 0 12 35 89

Wall 12 0 67 12

War 35 35 0 23

Etc... 56 43 76 0

But this is what I am getting

Hull Wall War Etc......

Hull 0 0 0 0

Wall 0 0 0 0

War 0 0 0 0

Etc... 0 0 0 0

**spydoor** · 05-08-2006

where is main

besides that your first line actually has 11 four character words not 10

**dgibson2004** · 05-08-2006

I cut the main out when posting on this forum to make the code shorter.

Here is the total code

Code:

#include <stdio.h>
#include <string.h>

int menu(void);
void cost(void);
void distance(void);
void showchart(void);


float  price;
int option, x, y, dist;

int grid[10][10];

char names[10][5];

main()
{

	int choice;

	choice = menu();
	
	while (choice<0 || choice >3)
	{
		choice = menu();
	}
	
	while (choice !=0)
	{
		switch (choice)
		{
			case 1:  distance(); break;
			case 2:  cost(); break;
			case 3:  showchart(); break;
		}
		choice = menu();
	}
	
	printf("\n***Thank you for using this programme!***\n");
}
			


int menu()
{

	int opt;

	printf("\n\n\nDo you want to\n");
	printf("<1>Calculate the distance between X and Y\n");
	printf("<2>Calculate the cost between X and Y\n");
        printf("<3>Display the chart\n");
	printf("<0>Quit\n\n\n");

	printf("Please enter your choice:  ");
	
	scanf("%d", &opt);

	printf("\n");
	
	return (opt);
}

void cost()
{
	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

	printf("Location 2:  ");
	scanf("%d", &y);

	while (y < 1 || y >10)
	{
		printf("\nPlease enter a valid Location 2:  ");
		scanf("%d", &y);
	}

	price = grid[x][y] * 0.4;
	
	printf ("\n");
	printf ("The price for your journey is: œ");
	printf ("%6.2f", price);
	printf ("\n");

}

void distance ()
{

	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

	printf("Location 2:  ");
	scanf("%d", &y);

	while (y < 1 || y >10)
	{
		printf("\nPlease enter a valid Location 2:  ");
		scanf("%d", &y);
	}

	dist = grid[x][y];
	
	printf ("\n");
	printf ("The distance for your journey is: ");
	printf ("%d", dist);
	printf (" miles\n");
}

void showchart ()
{
int x, row, col;

FILE *in_file;
in_file = fopen("places.txt","r");

for (x=0;x<=9; x++)
{
fscanf(in_file, "%4c", names[x]);
}

printf("\n     ");

for (x=0; x<=9; x++)
{
printf("%6s",names[x]);
}

printf("\n");
for (row=0; row<=9; row++)
{
printf("%s", names[row]);
	for(col=0; col<=9; col++)
{
	fscanf(in_file, "%d", &grid[row][col]);
	printf("%6d", grid[row][col]);
}
printf("\n");
}
fclose(in_file);
}

**dgibson2004** · 05-08-2006

I does contain 11 four letter names, I will delete the lastone and give that a go.

Thanks

**dgibson2004** · 05-08-2006

You were correct, the text file had 11 names instead of 10. Once I deleted the last name the program ran fine.

Thanks

**dude543** · 05-08-2006

In the function "distance" replace

Code:

dist = grid[x][y];

with

Code:

dist = grid[x-1][y-1];

Because array subscript starts with zero.

The same thing sould be done in function "cost" for
"price".

**dgibson2004** · 05-08-2006

thanks for that.

I had already resolved that issue all by myself

(wow I am clever)

but seriously thanks for pointing it out.

Just got to figure how to enter the start location and end destination by typing the place names and then displaying the mileage.

Any help on this would be appreciated as I have no clue where to start.

**dgibson2004** · 05-08-2006

Also anyone know how to tidy the following code up to make it look better, maybe put it under one function etc..... it works as it is but looks a bit untidy.

The code basically allows the user to input either 0, 1, 2 or 3 stops before the destination.

I have declared the variables in the top part of the code.

Code:

void distance ()
{
	int choice;

	choice = calcdis();
	
	while (choice<0 || choice >4)
	{
		choice = calcdis();
	}
	
	while (choice !=0)
	{
		switch (choice)
		{
			case 1:  dis0(); break;
			case 2:  dis1(); break;
			case 3:  dis2(); break;
			case 4:  dis3(); break;
                        case 5:  menu(); break;
		}
		choice = calcdis();
	}
	
	printf("\n***Thank you for using this programme!***\n");
}

int calcdis ()
{
int option;

	printf("\n\n\nHow many stops do you want?\n");
	printf("<1>No Stops\n");
	printf("<2>1  Stops\n");
        printf("<3>2  Stops\n");
	printf("<4>3  Stops\n");
	printf("<0>  Main Menu\n\n\n");

	printf("Please enter your choice:  ");
	
	scanf("%d", &option);

	printf("\n");
	
	return (option);
}
void dis0()

{

	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

	printf("Location 2:  ");
	scanf("%d", &y);

	while (y < 1 || y >10)
	{
		printf("\nPlease enter a valid Location 2:  ");
		scanf("%d", &y);
	}
        x = x-1;
        y = y-1;
	dist = grid[x][y];
	
	printf ("\n");
	printf ("The distance for your journey is: ");
	printf ("%d", dist);
	printf (" miles\n");
}


void dis1()

{

	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

	printf("Stop 1:  ");
	scanf("%d", &y);

	while (y < 1 || y >10)
	{
		printf("\nPlease enter Stop 1:  ");
		scanf("%d", &y);
	}


	printf("Location 2:  ");
	scanf("%d", &z);

	while (z < 1 || z >10)
	{
		printf("\nPlease enter a valid Location 2:  ");
		scanf("%d", &z);
	}
        x = x-1;
        y = y-1;
	z = z-1;

	dist1 = grid[x][y];
	dist2 = grid[y][z];
	dist = dist1 + dist2;
	printf ("\n");
	printf ("The distance for your journey is: ");
	printf ("%d", dist);
	printf (" miles\n");
}

void dis2()

{

	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

	printf("Stop 1:  ");
	scanf("%d", &y);

	while (y < 1 || y >10)
	{
		printf("\nPlease enter Stop 1:  ");
		scanf("%d", &y);
	}

	printf("Stop 2:  ");
	scanf("%d", &z);

	while (z < 1 || z >10)
	{
		printf("\nPlease enter Stop 2:  ");
		scanf("%d", &z);
	}
	
	printf("Location 2:  ");
	scanf("%d", &xz);

	while (xz < 1 || xz >10)
	{
		printf("\nPlease enter a valid Location 2:  ");
		scanf("%d", &xz);
	}
        x = x-1;
        y = y-1;
	z = z-1;
        xz = xz-1;

	dist1 = grid[x][y];
	dist2 = grid[y][z];
        dist3 = grid[z][xz];

	dist = dist1 + dist2 + dist3;

	printf ("\n");
	printf ("The distance for your journey is: ");
	printf ("%d", dist);
	printf (" miles\n");
}


void dis3()

{

	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

	printf("Stop 1:  ");
	scanf("%d", &y);

	while (y < 1 || y >10)
	{
		printf("\nPlease enter Stop 1:  ");
		scanf("%d", &y);
	}

	printf("Stop 2:  ");
	scanf("%d", &z);

	while (z < 1 || z >10)
	{
		printf("\nPlease enter Stop 2:  ");
		scanf("%d", &z);
	}
	
   	printf("Stop 3:  ");
	scanf("%d", &xz);

	while (xz < 1 || xz >10)
	{
		printf("\nPlease enter Stop 3:  ");
		scanf("%d", &xz);
	}

	printf("Location 2:  ");
	scanf("%d", &xy);

	while (xy < 1 || xy >10)
	{
		printf("\nPlease enter a valid Location 2:  ");
		scanf("%d", &xy);
	}
        x = x-1;
        y = y-1;
	z = z-1;
        xz = xz-1;
        xy = xy-1;

	dist0 = grid[x][y];
	dist1 = grid[y][z];
        dist2 = grid[z][xz];
	dist3 = grid[xz][xy];

	dist = dist0 + dist1 + dist2 + dist3;

	printf ("\n");
	printf ("The distance for your journey is: ");
	printf ("%d", dist);
	printf (" miles\n");
}

**itsme86** · 05-08-2006

Code:

void distance ()
{
	int choice;

	choice = calcdis();
	
	while (choice<0 || choice >4)
	{
		choice = calcdis();
	}
	
	while (choice !=0)
	{
		switch (choice)
		{
			case 1:  dis0(); break;
			case 2:  dis1(); break;
			case 3:  dis2(); break;
			case 4:  dis3(); break;
                        case 5:  menu(); break;
		}
		choice = calcdis();
	}
	
	printf("\n***Thank you for using this programme!***\n");
}

I would rewrite the above as:

Code:

void distance()
{
    int choice;

    do
    {
        choice = calcdis();

        switch(choice)
        {
            case 0: break;  // Do nothing. do-while will exit for us
            case 1:  dis0(); break;
            case 2:  dis1(); break;
            case 3:  dis2(); break;
            case 4:  dis3(); break;
            default: puts("BZZZZZZZT! Invalid option");
        }
    } while(choice);

    printf("\n***Thank you for using this programme!***\n");
}

I'm not sure where you got your switch case 5, because it's not part of the menu you show.

Also, you repeat this code a lot:

Code:

	printf("\nLocation 1:  ");
	scanf("%d", &x);

	while (x < 1 || x >10)
	{
		printf("\nPlease enter a valid Location 1:  ");
		scanf("%d", &x);
	}

You might consider making a function like so:

Code:

int get_location(char *dispstr)
{
  int var;

  do
  {
    printf("\nPlease enter a valid %s: ", dispstr);
    fflush(stdout);  // Should always flush stdout when not printing a newline
    sscanf("%d", &var);
  } while(var < 1 || var > 10);

  return var;
}

Then you can just call that for each location like so:

Code:

x = get_location("Location 1");

or

Code:

xz = get_location("Stop 1");

**dgibson2004** · 05-09-2006

Sorry the selection for case 5 just returns to the previous options.

I will give the code a try it certainely looks neater than the code I have writen.

what does

fflush(stdout); do? Not heard of this before.

Thanks

Dom

**whiteflags** · 05-09-2006

Originally Posted by man fflush(FILE *stream)

DESCRIPTION
If stream points to an output stream or an update stream in
which the most recent operation was not input, fflush(
causes any unwritten data for that stream to be written to
the file, and the st_ctime and st_mtime fields of the under-
lying file are marked for update.

If stream is a null pointer, fflush() performs this flushing
action on all streams for which the behavior is defined
above.

Now, in plain English:
Lets say you want to write to stdout to give the user some instructions. If you plug that statement in a loop and the last thing that happened was not the user typing, you will need to flush stdout to make sure that the statement is actually written.

Disclaimer: fflush(stdin) results in undefined behavior.

**dgibson2004** · 05-09-2006

Oh I see.

Thats for the explanation I will give it ago and see what results I get.

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