Thread: Reading in data from Text file

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];

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.

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

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

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 */
}

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.)

so try to extend your printf

Code:

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