test.c

#include "unistd.h"
#include "stdlib.h"
#include "stdio.h"

int main(void) {
    char* key = malloc(sizeof(char) * 20);
    key = "cookie";
    for (char i = 0; i < 20; ++i) {
        printf("[%c]", key[i]);
    }
    return 0;
}