1 #include     //printf 2 #include     //ssert 3 #include     //malloc 4 #include     //strlen 5  6 char * sstrcpy(char * strdst, char * strsrc) 7 { 8     char *dst = strdst; 9     assert(strdst!=NULL && strsrc!=NULL);10     while((*strdst++ = *strsrc++)!= ‘\0‘)11         NULL;12     return dst; //实现链式表达式13 }14 15 //int num = strlen(strcpy(strdst,"hello world"));16 17 int main(void)18 {19     int num;20     char *strdst = (char *)malloc(sizeof(char)*100);21 22     if(strdst == NULL)23         return (-1);24     num = strlen(sstrcpy(strdst,"hello world"));25     printf("%d\n", num);26 27     return 0;28 }