Thread: Writing an array in a file

Hello everyone! I'm not quite familiar with programming, so please go easy with me
I'm trying to write an array into a file and this is what i come up with:

Code:

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

char words[][2][40]={
      "adorer","adore",
      "gras","greasy",
      "outil","tool",
      "radis","radish",
      "tracer","trace",
      "",""
};

main()
{


    FILE *fp;
    int i;

    if(( fp=fopen( "myfile", "w" )) == NULL) {
        printf("Cannot open file.\n");
        exit(1);
    }

    fprintf( fp, "%s", words[i]);
    fclose(fp);

    if(( fp=fopen( "myfile", "r" )) == NULL) {
        printf("Cannot open file.\n");
        exit(1);
    }

    fscanf( fp, "%s", words[i]);
    printf(" %s", words);
    fclose(fp);

    return 0;
}

But it's not working. Any suggestions where am i wrong will be great.
By the way i'm running it on Turbo C++ 4.5, my operating system is XP and it gives me : "General Protection Exception... Processor Fault" and than i have to restart the compiler.

Code:

char words[][2][40]
...
    fprintf( fp, "%s", words[i]);

words[i] is not a string: it's an array of 2 strings (each of them with a maximum of 39 characters).

Try this

Code:

    fprintf( fp, "%s / %s\n", words[i][0], words[i][1]);

Note that words[i][0] (and words[i][1]) is indeed a string.

Three suggestions:
1. Turn on all warnings in your compiler. Warnings usually tell you that you're doing something wrong.
2. Fix each problem pointed out by the warnings. If you don't understand what a warning means or how to fix it, feel free to ask about it here, but be sure to copy and paste the complete warning and the complete program (if you made any changes since the first version you posted).
3. Get a different (better) compiler. Turbo C++ has a bad reputation among some people around here (I've never used it so I only know about its shortcomings secondhand).

Originally Posted by qny

Code:

char words[][2][40]
...
    fprintf( fp, "%s", words[i]);

words[i] is not a string: it's an array of 2 strings (each of them with a maximum of 39 characters).

Try this

Code:

    fprintf( fp, "%s / %s\n", words[i][0], words[i][1]);

Note that words[i][0] (and words[i][1]) is indeed a string.

When i do that and when i run the program(without errors) it only shows "adorer" on the screen and there is no text file in the directory.

Originally Posted by Marria

... it only shows "adorer" on the screen ...

You need to print (and write to the file) in a loop.

Originally Posted by Marria

... there is no text file in the directory.

Perhaps you meant "myfile.txt" rather than "myfile" with no extension?

Originally Posted by qny

words[i] is not a string: it's an array of 2 strings (each of them with a maximum of 39 characters).

It's actually 40. Just because the first one is at subscript 0 doesn't change the total. C isn't messing with you.

Originally Posted by whiteflags

It's actually 40. Just because the first one is at subscript 0 doesn't change the total. C isn't messing with you.

The first one being 0 is not the problem. The problem is the last one (at whatever position it happens to be, including position 39) having a value of 0 and not counting towards the length of the string.

The string "hello" has 5 characters, but it is an array of size 6.

Well I guess that's a way of looking at it.

Christop i really want to change this compilar but the professor uses and so am i. As for the warnings - i'm still searching the answers in the net

Stick with what you are using now. Don't get caught doing a good program, and then having it marked down because you used a different compiler than the one the professor is using.


Give this a look over with your compiler, and see how it does:

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
char words[][2][40]= {
      {"adorer","adore"},
      {"gras","greasy"},
      {"outil","tool"},
      {"radis","radish"},
      {"tracer","trace"},
      {"",""}
};
 
int main(void)
{
 
 
    FILE *fp;
    int i;
 
    if(( fp=fopen( "myfile", "w" )) == NULL) {
        printf("Cannot open file.\n");
        exit(1);
    }
    //print out the original string array to the file
    for(i=0;i<6;i++) {
       fprintf( fp, "%s %s ", words[i][0], words[i][1]);
    }
    fclose(fp);
   //show the original string array 
   for(i=0;i<6;i++) {
       printf( "%s, %s, ", words[i][0], words[i][1]);
    }

    if(( fp=fopen( "myfile", "r" )) == NULL) {
        printf("Cannot open file.\n");
        exit(1);
    }
 
   //reread the file strings
   for(i=0;i<6;i++) {
    fscanf( fp, "%s %s ", words[i][0], words[i][1]);  
   }
   fclose(fp);

   printf("\n\n Reloaded values from the file are:\n");
    for(i=0;i<6;i++) {
       printf( "%d: %s, %s, \n", i,words[i][0], words[i][1]);
    }
   printf("\n");
 
    return 0;
}