C++程序练习小游戏1：系统给出一个随机数，用户来猜大小，猜一次系统给出提示是猜大了还是猜小了，知道猜中那个数为止

#include <iostream>
#include<stdlib.h>
#include <string>
//调试f10执行下一步，f11执行下一句
using namespace std;

int main ()
{
	cout << "game start:" << endl;
	cout << "please input a number between 0-100: " << endl;

	int play_again = 1;
	int true_num= 0, guess_num = 0;
	int flag = 1;
	string user_choise;
	string y = "y";
	string Y = "Y";
	string n = "n";
	string N = "N";
	while(1)
	{
		if (play_again == 1 && (true_num == guess_num) )//再玩一次程序
		{
			true_num = rand()%(101);	//产生一个随机数
			cout << "please input your guessing number: " << endl;
			cin >> guess_num;	//用户猜测
		}
		if ((guess_num != true_num)&& (flag !=1))//多次猜测
		{
			cin >> guess_num;
		}

		if(guess_num != true_num)//猜错了
		{
			if (guess_num > true_num )
			{
				cout << "the true num is smaller " <<endl;

				flag ++;
			}
			if (guess_num < true_num)
			{
				cout << "the true num is bigger " <<endl;

				flag ++;
			}
		}

		if (guess_num == true_num)//猜对了
		{
			cout << "Guess right !" <<"Do u want to play again? please input 'Y' or 'N'  " << endl;
			cin >> user_choise; 
			if ((user_choise == y) || (user_choise == Y) )
			{
				play_again = 1;
				flag = 1;
			}
			if ((user_choise == n) || (user_choise == N) )
			{
				play_again = 0;
				flag = 1;
				break;
			}
		}

		}

	system("pause");
	return 0;
}