自己实现strcpy函数

 #include     //printf
 #include     //ssert
 #include     //malloc
 #include     //strlen

 char * sstrcpy(char * strdst, char * strsrc)
 {
     char *dst = strdst;
     assert(strdst!=NULL && strsrc!=NULL);
     while((*strdst++ = *strsrc++)!= '\0')
         NULL;
     return dst; //实现链式表达式
 }

 //int num = strlen(strcpy(strdst,"hello world"));

 int main(void)
 {
     int num;
     char *strdst = (char *)malloc(sizeof(char)*);

     if(strdst == NULL)
         return (-);
     num = strlen(sstrcpy(strdst,"hello world"));
     printf("%d\n", num);

     return ;
 }