Question

Filling binary (byte) integers values into array from a file and returning a pointer pointing at array, I'm using C programming language

Here is my code https://pastebin.com/xp7wSZgj

My output: https://pastebin.com/VU6JGWcX

My issue is my buffer array isn't being allocated, that's why I commented out free. fread() isn't reading in all the values! How do I fix that? Detailed explanation and how I can go about fixing it. Only the first value is taken in by the array also  I'm student no advanced concepts

Answer 1

#######################################
           input.txt
#######################################
4 5 6 7 7 8



#######################################
              main.c
#######################################
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>


int *read_int_deltas(char *fname, int *len){

    int maxLen = 100;
    int count = 0;

    FILE* fpointer;
    int* buffer;
    fpointer = fopen(fname, "r");

    if(fpointer == NULL){
        *len=-1;
        return NULL;
    }

    buffer = (int *)malloc((maxLen)*sizeof(int));

    while(fscanf(fpointer, "%d", &buffer[count]) != EOF) {
        count++;
    }   
    fclose(fpointer);

    *len = count;

    for(int i=0; i<count; i++) {
        printf("%d
", buffer[i]);
    }

    //free(buffer);
    return buffer;
}

int main(void) {
    int l;
    read_int_deltas("input.txt", &l);
    return 0;
}

================

Try this code.. It works

Why your code doesn't work=>
You are reading the file size in bytes, and then dividing it by 4 to get how many integers should be present.. but that is not correct..

Because file holds everything in form of characters only, and one character is 1 byte only.. So if file contains "4321", then its size is 4 bytes.. If you divide it by size of integer, you get value 1, but that is not correct.. because you need 4 integers instead of 1 integer..
hence i am taking a sufficiently large array, and then putting required number of values into that. Let me know if any issues.