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

int main(int argc, char* argv[]) {

    int* a_n = malloc(sizeof(*a_n));
    // BAD WAYS:
    // int* a_n = (int*) malloc(sizeof(*a_n)); // BAD: Do not use typecast.
    // int* a_n = malloc(sizeof(int));         // BAD: Use sizeof with a variable, not
    //                                                 a type.
    // int* a_n = (int*) malloc(sizeof(int));  // BAD: Both problems (↑↑)  BAD BAD!!!!
    // int* a_n = malloc(4);                   // BAD: Requires remembering size of type
    //                                                 AND may break when you move code
    //                                                 to a different platform.


    *a_n = 5; // Store (value) 5 at (address) a_n.
    
    printf("*a_n = %d\n", *a_n);

    free(a_n); // Deallocate the heap allocation block that begins at (address) a_n.

    return EXIT_SUCCESS;
}
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