C++primer习题3.21

就是上一个题目的改写，灰常简单：

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


int main()
{
  string cur,pre;
  bool flag = true;
  cout << "Please input string: " ;
  while (cin >> cur )
  {
    if (cur == pre && cur[0] >= 'A' && cur[0] <= 'Z')
    {
		  cout << "The repeat words are "<<cur <<endl;
    }
	else
	{
		cout << "Please input string: " ;
		pre = cur;
	}
  }
 
}