airportsimulation.h

机场系统

//模拟程序
#ifndef AIRPORTSIMULATION_H
#define AIRPORTSIMULATION_H

#include<iostream>
using std::cout;
using std::endl;
using std::cin;

#include <cmath>
#include <ctime>

#include "Queue.h"

struct plane                                //飞机描述
{
  int id;                                   //编号
  int tm;                                   //到达队列时间
};

enum action { ARRIVE , DEPART };            //飞机的动作

class AirportSimulation                     //机场模拟。一个时间单元=一架飞机起飞或降落的时间
{
	public:
		AirportSimulation( );               //构造函数
		void RunSimulation( );              //模拟运行
	private:
		Queue<plane> landing;               //等待降落的飞机队列，假设用环形队列
		Queue<plane> takeoff;               //等待起飞的飞机队列，假设用环形队列

		double expectarrive;                //一个时间单元内期望到达的降落的飞机数
		double expectdepart;                //一个时间单元内期望到达的起飞的飞机数

		int curtime;                        //当前时间
		int endtime;                        //模拟时间单元数

		int Firstidletime;                  //第一跑道空闲时间单位数
		int Secondidletime;                 //第二跑道空闲时间单位数
		int Thirdidletime;                  //第三跑道空闲时间单位数

		int landwait;                       //降落飞机的总等待时间
		int takeoffwait;                    //起飞飞机的总等待时间

		int nland;                          //降落的飞机数
		int ntakeoff;                       //起飞的飞机数
		int nplanes;                        //处理的飞机数
		int nrefuse;                        //拒绝服务的飞机数
		
		void Randomize();                   //设置随机数种子
		int PoissionRandom( double& expectvalue );      //根据泊松分布和个定期望值生成随机非负整数

		plane* NewPlane( plane& p , action kind );	    //建立新飞机的数据项

		void Refuse( plane& p , action kind );          //拒绝服务
		void Land( plane&, int );                       //降落飞机             
		void Fly( plane&, int );                        //起飞飞机

		void Idle(int);                                 //处理空闲时间单元
		void Conclude();                                //总结模拟结果
};

AirportSimulation::AirportSimulation( )                 //构造函数
{
	bool ok;

	cout << "请输入模拟时间单元数:";
	cin >> endtime;

	Firstidletime = Secondidletime = Thirdidletime 
		          = landwait = takeoffwait 
				  = nland = nplanes = nrefuse = ntakeoff = 0;     //初值

	Randomize();                                        //设置随机数种子

	do
	{
		cout << "请输入一个时间单元内期望到达降落的飞机数:";   
		cin >> expectarrive;

		cout << "请输入一个时间单元内期望到达起飞的飞机数:";    
		cin >> expectdepart;

		if( expectarrive < 0.0 || expectdepart < 0.0 ) 
		{
			cout << "这些数不能为负!请重新输入。" << endl;  
			ok = false;
        } 
		else if( expectarrive > 2.0 || expectdepart > 2.0 || expectarrive + expectdepart > 3.0 )
		{
			cout << "机场将饱和!请重新输入。" << endl;  
            ok = false;
        }
		else 
			ok = true;
	}
	while( !ok );
}

void AirportSimulation::RunSimulation()                //主控程序
{
    int pri;                                            //伪随机整数
    plane p; 
    for( curtime = 1 ; curtime <= endtime ; curtime++ ) 
	{
		cout << "时间单元" << curtime << ":" << endl;
		pri = PoissionRandom( expectarrive );

		for( int i = 1 ; i <= pri ; i++ )               //处理新到达的准备降落的飞机
		{
			p = *NewPlane( p , ARRIVE );                //建立飞机对象

			if( landing.GetSize() >= 6 )
				Refuse( p , ARRIVE ); 
			else 
				landing.Add( p );
		}
		pri = PoissionRandom( expectdepart );

		for ( int j = 1 ; j <= pri ; j++ ) 
		{
			p = *NewPlane( p , DEPART );

			if( takeoff.GetSize() >= 6 )
				Refuse( p , DEPART ); 
			else 
				takeoff.Add( p);
		}
		
		bool Thirdused = false;                          //只要降落队列不空，降落优先
		if( landing.GetSize() > 0 )
		{
			p = *landing.Delete( p );
			Land( p , 1 );                               //若有飞机等待降落，第一降落专用跑道先用

			if( landing.GetSize() > 0 )                     //若还有飞机等待降落，第三跑道优先降落
			{
				p = *landing.Delete( p );
				Land( p , 3 );

				Thirdused = true;                         //第三跑道标志已使用
			}
		}
		else 
			Idle( 1 );

		if( takeoff.GetSize() > 0 )                          //若有飞机等待起飞，第二起飞专用跑道先用
		{
			p = *takeoff.Delete( p );
			Fly( p , 2 );
			if( Thirdused == false && takeoff.GetSize() > 0 ) //第三跑道未用且有飞机等待起飞的情况下
			{                                              //该跑道用于起飞
				p = *takeoff.Delete( p );
			    Fly( p , 3 );
				Thirdused = true;
			}
		}
		else 
			Idle( 2 );

		if( Thirdused != true )                            //第三跑道空闲
			Idle( 3 );
	}
    Conclude();
}

void AirportSimulation::Randomize()                         //用库函数srand和rand生成随机数.
{                                                           //用时钟设置随机种子,以增强随机性。
    srand( ( unsigned int ) ( time( NULL ) % 10000 ) );
}

int AirportSimulation::PoissionRandom( double& expectvalue ) 
{
	int n = 0;                                               //循环计数
	double limit;                                            
	double x;                                                //伪随机数

	limit = exp( -expectvalue );	
	x = rand() / ( double ) 30000;	

	while ( x > limit ) 
	{
		n++;
        x *= rand() / (double) 30000;
    }

    return n;
} 

plane* AirportSimulation::NewPlane( plane& p, action kind )  //建立新飞机数据项
{
	nplanes++;                                               //飞机总数加1

	p.id = nplanes; 
	p.tm = curtime;

	switch ( kind ) 
	{
		case ARRIVE:
			cout << "  飞机" << nplanes << "准备降落。" << endl;
			break;
		case DEPART:
			cout << "  飞机" << nplanes << "准备起飞。" << endl;
			break;
	}
    return &p;
}

void AirportSimulation::Refuse( plane& p , action kind )       //处理被拒绝的飞机
{
	switch( kind ) 
	{
		case ARRIVE:
			cout << "  引导飞机" << p.id << "到其它机场降落。" << endl;
            break;
        case DEPART:
            cout << "  告诉飞机" << p.id << " 等一会儿再试。" << endl;
            break;
    } 
    nrefuse++;
}

void AirportSimulation::Land( plane& p , int n )           //处理飞机降落时同时传入使用跑道数
{
    int wait;

    wait = curtime - p.tm;

    cout << "  飞机" << p.id << "降落" << n << "跑道，该机等待时间:" << wait << "。" << endl;

    nland++;                                               //降落飞机总数加1
    landwait += wait;                                      //累加总降落等待时间
}

void AirportSimulation::Fly( plane& p , int n )            //处理飞机起飞时同时传入使用跑道数
{
    int wait;
	
	wait = curtime - p.tm;

    cout << "  飞机" << p.id << "起飞" << n << "跑道，该机等待时间:" << wait << "。" << endl;

    ntakeoff++;                                            //起飞飞机总数加1 
    takeoffwait += wait;                                   //累加总起飞等待时间
}

void AirportSimulation::Idle( int n )                      //处理机场空闲，分别处理
{
    cout << "  跑道 " << n <<" 空闲。" << endl;

    switch( n ) 
	{
		case 1:
			Firstidletime++;
			break;
        case 2:
            Secondidletime++;
			break;
		case 3:
            Thirdidletime++;
			break;
    }
}

void AirportSimulation::Conclude() 
{
	cout << endl << endl << "总模拟时间单元数: " << endtime << endl;

    cout << "总共处理的飞机数: " << nplanes << endl;
    cout << "降落飞机总数: " << nland << endl;
    cout << "起飞飞机总数: " << ntakeoff << endl;
	cout << "拒绝服务的飞机总数: "<< nrefuse << endl;
    cout << "队列中剩余的准备降落飞机数: " << landing.GetSize() << endl;
    cout << "队列中剩余的准备起飞飞机数: " << takeoff.GetSize() << endl;

    if( endtime > 0 ) 
		cout << "跑道空闲时间百分比:" << endl
		     << "  First Track: " << ( ( double ) Firstidletime / endtime ) * 100.0 << endl
		     << "  Second Track: " << ( ( double ) Secondidletime / endtime ) * 100.0 << endl
		     << "  Third Track:" << ( ( double ) Thirdidletime / endtime ) * 100.0 << endl;
   
	if( nland > 0 ) 
		cout << "降落平均等待时间: " << ( double ) landwait / nland << endl;
    
	if( ntakeoff > 0 ) 
		cout << "起飞平均等待时间: " << ( double ) takeoffwait / ntakeoff << endl;
}

#endif