test.c

#include "stdio.h" // includes definiton of printf
#include "stdlib.h" // includes definiton of malloc

void copy_string(char *dest, char *src) {
    // Copy bytes from src into dest
    while ((*(dest++) = *(src++))) {};
}


int main(){
    char *hello_msg = "Hello, World!";
    char *dest = malloc(30);
    // Returns a pointer to 30 bytes of free space somewhere in memory
    char *yourname = "Elamind!";

    printf("%s\n", dest);
    copy_string(dest,  hello_msg);
    printf("%s\n", dest);
    copy_string(dest+7,  yourname);
    printf("%s\n", dest);


    return 0;
}