C++程序设计语言练习7.9 迭代器的使用

我的代码如下：

#include <iostream>#include <string>using std::cin;using std::cout;using std::endl;using std::string;int main(){  string s,key;  cout<<"please input the words need to encrypt"<<endl;  cin>>s;  cout<<"please intpu the encrypt key"<<endl;  cin>>key;  if (key.empty()) {    return -1;  }  string::iterator key_iter = key.begin();  for (string::iterator s_iter = s.begin(); s_iter != s.end(); s_iter++) {    *s_iter = *s_iter ^ *key_iter++;    if (key_iter == key.end()) {      key_iter = key.begin();    }  }  cout<<s;  return 0;}

迭代器的使用