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

int main(int argc, char* argv[]) {
    char* s = malloc(sizeof(*s) * 3);
    s[0] = 'a';
    s[1] = 'b';
    s[2] = '\0';
    free(s);
    s = NULL;

    // NULL is a symbolic constant that we use when an address variable does not contain an address.
    // Numerically, it is the address 0.  0 is an address that we must not touch.

    s[0] = 'i';
    printf("s == \"%s\"\n", s);  // BAD!!!

    // We will also use NULL whenever we want to say "nothing" e.g., an empty array or linked list.
    
    return EXIT_SUCCESS;
}
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