我用迭代器的做的，感觉还是没搞懂输入的字符串有空格时是什么情况，所以直接用了getline int main() { string s; getline(cin, s); s.insert(s.begin(), ' '); auto iter = s.end(); auto end_iter = iter; auto OverIter = s.begin() ; while (iter != OverIter) { iter--; if (*iter == ' ') { auto tmpIter = iter+1; while (tmpIter != end_iter) { cout << *tmpIter; tmpIter++; } cout << " "; end_iter = iter; } } return 0; }