[C] Dangling pointer demo

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

int main() {
    const int SIZE = 10;

    // Allocate memory for the array a.
    int* a = (int*) malloc(SIZE * sizeof(int));

    // Set the value in a
    for (int i = 0; i < SIZE; i++) {
        int j = i + 1;
        a[i] = j * j;
    }

    // Share the address of a to a1
    int* a1 = a;

    // Oh, the memory of a is freed!
    free(a);
    a = NULL;

    /* Now a1 becomes dangling pointer.
       Accessing data via a dangling pointer is
       an undefined behavior. */
    printf("%d\n", a1[3]);

    return 0;
}