Question

How to pass a pointer to a function and allocate an array in C

Answer 1

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

#define LEN 7

void allocateAndInitializeArray(int** arr, int size) {
    *arr = (int*)malloc(size * sizeof(int));

    if (*arr == NULL) {
        printf("Memory allocation failed");
        exit(EXIT_FAILURE);
    }

    for (int i = 0; i < size; i++) {
        (*arr)[i] = i * 3;
    }
}

int main(void)
{
    int* arr = NULL;

    allocateAndInitializeArray(&arr, LEN);

    for (int i = 0; i < LEN; i++) {
        printf("arr[%d] = %d\n", i, arr[i]);
    }

    free(arr);

    return 0;
}




/*
run:

arr[0] = 0
arr[1] = 3
arr[2] = 6
arr[3] = 9
arr[4] = 12
arr[5] = 15
arr[6] = 18

*/

 

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