练习31

#include <iostream>
#include <string>
using namespace std;


string reverse(string& str) {
if (str.length() > 1) {
string sub = str.substr(1, str.length() - 2);
return str.substr(str.length() - 1, 1) + reverse(sub) + str.substr(0, 1);
} else
return str;
}


int main() {
string str;
cout << "输入一个字符串：";
cin >> str;
cout << "原字符串为：" << str << endl;
cout << "倒序反转后为：" << reverse(str) << endl;
return 0;
}