Question

I want a simple C program, which will read a file and saves the content of each line to an array element. The file contains all the integer value. Only one integer value is present per line. In this way each of the integer value is to stored in an array.

Answer 1

Here is an example which does what you ask, with error checking, and dynamically resizing your array as more data is read in.

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

int main(int argc, char ** argv)
{
    char buf[512];
    FILE * f;
    int * array = 0;
    size_t array_len = 0, count = 0;

    if (argc != 2) {
        fprintf(stderr, "Please provide a filename to read\n");
        exit(1);
    }

    f = fopen(argv[1], "r");

    if (f == NULL) {
        perror("fopen");
        exit(1);
    }

    while (fgets(&buf[0], 512, f) != 0) {
        if (count == array_len) {
            array_len *= 2;
            if (array_len == 0) {
                array_len = 32;
            }
            array = realloc(array, array_len * sizeof(int));
            if (array == NULL) {
                perror("realloc");
                exit(1);
            }
        }
        array[count++] = strtol(buf, 0, 10);
    }

    return 0;
}