Copying a string to the heap – output Answer, explanation & discussion

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

int main(void) {
    const char *src = "heap";
    char *copy = malloc(strlen(src) + 1);
    if (copy == NULL)
        return 1;
    strcpy(copy, src);
    copy[0] = 'H';
    printf("%s %s %zu\n", src, copy, strlen(copy) + 1);
    free(copy);
    return 0;
}