C++猜数字游戏的程序，用srand()函数才生随机数

/*

编写一个猜数字游戏的程序:程序随机选择一个1到1000的数，然后输出：

I have a number between 1 and 1000．

Can you guess my number?

Please type your first guess：

接着，游戏者输入一个结果。程序根据比较结果输出以下三条信息之一：

1)Excellent! You guessed the number!

Would you like to play again (y or n)?

2)Too low．Try again．

3)Too high．Try again．

如果游戏者猜错，则程序进行循环，直到猜对。程序通过Too high或Too low消息帮助学生接近正确答案。请思考：怎样才能猜得最快？

*/

<span style="font-size:14px;">#include<iostream>
#include <cstdlib>
#include<time.h>
using namespace std;
int RNG()			//此函数用于产生随机数 
{
	int Random_number;
	srand(time(0));<span style="white-space:pre">	</span>//获取系统时间来作为种子
	Random_number=1+rand()%1000;	
	return Random_number;
}
int main()
{
	int Random_number,guss_number;
	char yes_no;
	while(true)
	{
		Random_number=RNG();
		cout<<Random_number<<endl;//输出系统产生的随机数，免得难得猜。
		cout<<"I have a number between 1 and 1000"<<endl;
		cout<<"Can you guess my number?"<<endl;
		cout<<"Please type your first guess：";
		cin>>guss_number;
		while(guss_number<1||guss_number>1000)
		{
			cout<<"Input error,once again!";
			cin>>guss_number;
		} 
		while(true)
		{
			if(guss_number==Random_number)
			{
				cout<<"Excellent! You guessed the number!"<<endl;
				cout<<"Would you like to play again (y or n)?：" ;
				cin>>yes_no;
				if(yes_no=='n')
				{
					exit(0);	//返回操作系统 
				}
				else
				{
					break;		//跳出第一层循环 
				}
			}
			if(guss_number<Random_number)
			{
				cout<<"Too low．Try again ";
				cin>>guss_number;
				while(guss_number<1||guss_number>1000)
				{
					cout<<"Input error,once again!";
					cin>>guss_number;
				} 
			}
			if(guss_number>Random_number)
			{
				cout<<"Too high．Try again ";
				cin>>guss_number;
				while(guss_number<1||guss_number>1000)
				{
					cout<<"Input error,once again!";
					cin>>guss_number;
				} 
			}
		}
	}
	return 0;
} </span>

运行截图如下：