Thread: Converting a file to an array

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Hi, how can i write a C program in Red Hat 9. I can't find a compiler.
Also would you mind looking at this code and telling me if you think its ok. I need to put a file which has many columns of data (of which i only need the first two) into an array, so that i can add it to another such file. This is prob very basic, but C is a bit of a mystery to me and i'm only beginning to find my way.

Code:

#include<stdio.h>
void main()
{
int i,j,array1[][2];
FILE *inp;
inp=fopen("file1.txt","r");
for(i=0;i!=EOF;i++)
for(j=0;j<2;j++)
{
fscanf(inp,"%d",&array1[i][j]);
}
fclose(inp);
}

What do you reckon? How can i show if this worked, would some simple printf command work? Oh, and to put the final array back into a file? Is that just fprintf? Thanks very much for any help you can provide.

Is there any particular reason you are using Redhat 9? Its pretty old now so if possible you should install Fedora Core. Anyhow, the the main compiler used on Linux is gcc. Most Linux distributions either include it as default, or else the installation allows you to select whether or not to install it. Redhat 9 I think does not install gcc by default but there are various ways to install it post install if you need to

Originally Posted by Boucho

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Hi, how can i write a C program in Red Hat 9. I can't find a compiler.
Also would you mind looking at this code and telling me if you think its ok. I need to put a file which has many columns of data (of which i only need the first two) into an array, so that i can add it to another such file. This is prob very basic, but C is a bit of a mystery to me and i'm only beginning to find my way.

Code:

#include<stdio.h>
void main()
{
int i,j,array1[][2];
FILE *inp;
inp=fopen("file1.txt","r");
for(i=0;i!=EOF;i++)
for(j=0;j<2;j++)
{
fscanf(inp,"%d",&array1[i][j]);
}
fclose(inp);
}

What do you reckon? How can i show if this worked, would some simple printf command work? Oh, and to put the final array back into a file? Is that just fprintf? Thanks very much for any help you can provide.

So you basically need to read in a file and append it to another file? Why don't you just put fgets in a while loop until EOF and put each line you get into the other file.
Or in linux it would be easier just to do...

Code:

cat fromfile.txt >>tofile.txt

Though I assume this is a learning exercise of sorts.
Your current code has issues.. like main returns an int.
And I have no clue what you're trying to achieve with this line..

Code:

for(i=0;i!=EOF;i++)

Are you trying to go until it hits end of file? Because that isn't going to do it. Actually that loop would be endless on my system since EOF is defined as -1.

Code:

#include<stdio.h>

int main()
{
    FILE *fp;
    int array[1][5];
    int i,ch,j;
    
    if((fp = fopen("file.txt","r"))==NULL)
    {
        printf("Error: File cannot be opened");
        getchar();
        return 1;
    }
    else
    {
        for(i=0 ;i<2;i++)
        {
            for(j=0;j<5;j++)
                fscanf(fp,"%d",&array[i][j]);
        }
    }
    
    for(i=0;i<2;i++)
    {
        for(j=0;j<5;j++)
            printf("%d\t",array[i][j]);
        printf("\n");
    }
    
    fclose(fp);
    getchar();
    return 0;
}
/* my output
1       2       3       4       5
6       7       8       9       10


my File.txt
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
16 17 18 19 20
*/

ssharish2005

> int array[1][5];
Surely you mean
int array[2][5];

thax Salem u are right thats my bad

ssharish2005