C++程序设计语言练习7.9 迭代器的使用

#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;
}