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

static const char separators[] = " \r\n\t,.-";

void read_ints(char *filename, int **output_array, int *count)
{
    FILE *f;
    int *array, allocated_size = 4;
    char line[256];

    if(!(f = fopen(filename, "r"))) {
        printf("unable to open '%s': %s\n", filename, strerror(errno));
        exit(1);
    }

    *count = 0;
    array = malloc(sizeof(int) * allocated_size);
    while(fgets(line, sizeof(line), f)) {
        for(char *token = strtok(line, separators); token; token = strtok(NULL, separators)) {
            array[(*count)++] = atoi(token);
            if(*count == allocated_size) {
                allocated_size *= 2;
                array = realloc(array, sizeof(int) * allocated_size);
            }
        }
    }
    fclose(f);

    *output_array = array;
}

int main()
{
    int *some_ints, num_ints;

    read_ints("filename.txt", &some_ints, &num_ints);
    printf("read %d integers:\n", num_ints);
    for(int i = 0; i < num_ints; i++)
        printf("%d\n", some_ints[i]);

    free(some_ints);
    return 0;
}