//Argument: s - pointer to a C-style string
//Return value: A pointer to a NEW C-style string that contains the exact same characters
//as parameter s
char* clone(const char *s){
   int i;
   char *c=calloc(length(s),sizeof(s));
   for(i=0;i<length(s);i++){
      c[i]=s[i];
   }
   return c;
}//clone()

void main(){
   char *cl=clone(s1);
   printf("clone: %s\n", cl);
}