C++键盘输入，判断yes or no？

#include <iostream>
using namespace std;
int main()
{
	cout << "<y/n>";
	char ch;
	cin >> ch;
	if (ch == 'y' || ch == 'Y')
		cout << "肯定\a\n";
	else if (ch == 'n' || ch == 'N')
		cout << "否定\a\n";
	else
		cout << "退出\a\n";
	system("pause");
	return 0;
}