面试C＋＋试题[9]

#include <iostream>

char *strcpy_x(char *strdest, const char *strsrc)

{

    if((strdest==null) || (strsrc ==null))

       return null;       // 2分

    if(strdest==strsrc)//add by xie

       return strdest;  

    char *address = strdest;                                     // 2分

    while( (*strdest++ = * strsrc++) != '\0' )              // 2分

        ;

   return address ;                                          // 2分

}

class string

       {

         friend std::ostream& operator <<(std::ostream& os, const string& arg);       //add by xie