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Q: Storing data from a text file into an array ( Answered,   0 Comments )
Subject: Storing data from a text file into an array
Category: Computers > Programming
Asked by: perry1872-ga
List Price: $10.00
Posted: 14 Apr 2006 08:18 PDT
Expires: 14 May 2006 08:18 PDT
Question ID: 718864
Hello there,

We are using a optimization tool called CPLEX and the inputs for this
program is fed from a text file which contains a matrix with rows and
colums (max rows and colums will be 100 X 100).

I know how to call a C program into this optimization tool.

 I want to know how to store this data in array [i][j] from the text
file, the delimiter used is comma ",".

The text file say network.txt looks something like this.


I need  this to be stored in array [i][j]. The program should strictly
be in C only.


p.s: Bonus will be given too
Subject: Re: Storing data from a text file into an array
Answered By: hammer-ga on 14 Apr 2006 09:15 PDT

This C program will do what you want. You can change the variable
declaration to expand the matrix beyond 100 elements. You cn also
change the filename from network.txt to whatever you need it to be.

NOTE: You may need to unwrap lines wrapped by the answer box.

// ------------- CODE BEGIN -------------

#include <stdio.h>

void	main()
int	n[100][100];
int	i;
int	j;
int	a;
int	di;
int	dj;
int	quit;
FILE	*fp;
char	line[1024];
char	*cp;

	i = 0;
	quit = 0;
	fp = fopen("network.txt", "r");
	if(fp != NULL)
		while((fgets(line, 1024, fp)) && (quit == 0))
			j = 0;
			cp = line;
			while((*cp != '\0') && (quit == 0))
				a = atoi(cp);
				if((i < 100) && (j < 100))
					n[i][j] = a;
					while((*cp != ',') && (*cp != '\0')) cp++;
					if(*cp == ',') cp++;
					quit = 1;
					fprintf(stderr, "Error: Rows or columns has exceeded 100. Exiting
		// DEBUG loop to print out array contents
		if(quit == 0)
			for(di = 0; di < i; di++)
				printf("ROW %d : ", di);
				for(dj = 0; dj < j; dj++)
					printf("%d	", n[di][dj]);
		fprintf(stderr, "Error: Unable to open network.txt.\n");

// ------------- CODE END -------------

Good luck with CPLEX!

- Hammer

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None. Wrote a C program per stated requirements.
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