Implementing a string copy function in C

Question

At a recent job interview, I was asked to implement my own string copy function. I managed to write code that I believe works to an extent. However, when I returned home to

Answer 1

char * mycpy (char * destination, char * source) {

  if (!destination || !source) return NULL;

  char * tmp = destination;

  while (*destination != NULL || *source != NULL) {
    *destination = *source;
    destination++;
    source++;
  }

  return tmp;
}

In the above copy implementation, your tmp and destination are having the same data. Its better your dont retrun any data, and instead let the destination be your out parameter. Can you rewrite the same.