Programming

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.

#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.

1. the gcc compiler is distributed as part of RH. try:

Code:

find /usr -name gcc

2. Do not use void main() - it is int main()

Code:

int main( int argc, char *argv[])
{

    ......
    ......
    return 0;   <- last line in main()
}

3. the loop will not work to read a file

Code:

for(i=0;;i++)
{
  test for EOF here
}

so many more errors.... On second thought, you need a C book. try Herbert Schild's book 'Complete C Reference' or one of the SAM's books on C.

As for your problem - it can be done in a few lines of awk code.

Code:

awk ' {print $1, $2}' myfile > newfile

newfile will have the first two columns of myfile.