#include<iostream.h>
//typedef long size_t  ;

size_t  stlen(const char *s)
 {
   size_t n;
   for(n=0;*s!='\0';++s)               // counter  without '\0'
      ++n;
   return n;
 }

char *stcpy(char *s1,register const char *s2)
  {
    register char *p=s1;

    while(*p++ = *s2++)               // copy
	 ;
    return s1;
  }

char *stcat(char *s1,register const char *s2)
  {
    register char *p=s1;
    while(*p)    // go to the end of s1
      ++p;
    while(*p++ = *s2++)       // copy
	  ;
    return s1;
  }