编写一个满足下述练习中描述的程序，但使用string对象而不

#include<iostream>
#include<string>
using namespace std;
int main()
{
 string s;
 int sum = 0,i = 0;
 cout << "Enter words(to stop,type the word done):\n";
 cin >> s;
 while(1)
 {
  i = 0;
  if (s[i] == 'd' && s[i + 1] == 'o' &&
   s[i + 2] == 'n' && s[i + 3] == 'e' && s.length() == 4) {
   break;
  }
  sum++;
  cin >> s;
 } 
 cout << "Your entered a total of " << sum << " words." << endl;
   return 0;
}