华为面试题：

char *mystrcpy(char *dest,char *src,int n) 

 { 

     char *newdest = dest; 

     assert((dest != NULL) && (src != NULL)) 

     while (n &&((*dest++ = *src++) != '\0')) 

     { 

         n--; 

     } 

     if (n) 

     { 

         while (--n) 

             *dest = '\0'; 

     } 

     return newdest; 

 }