simula.cpp

这是本人精心搜集的关于常用图论算法的一套源码

#include <iostream.h>
#include <time.h>
#include "random.h"
#include "Plane.H"
#include "Runway.H"

void main( )   // Airport simulation program
/* Pre: The user must supply the number of time intervals the simulation is to run, the
        expected number of planes arriving, the expected number of planes departing
        per time interval, and the maximum allowed size for runway queues.
   Post: The program performs a random simulation of the airport, showing the status of
         the runway at each time interval, and prints out a summary of airport operation
         at the conclusion.
   Uses: ClassesRunway ,Plane ,Random and functionsrun run_idle ,initialize . 
*/
{ int end_time;   //time to run simulation
  int queue_limit; //size of Runway queues
  int flight_number = 0;
  double arrival_rate, departure_rate;
  void initialize(int&, int&, double&, double&);
  void run_idle(int);

  initialize(end_time, queue_limit, arrival_rate, departure_rate);
  Random variable; 
  Runway small_airport(queue_limit);
  for(int current_time=0; current_time<end_time; current_time++) 
   {
     int number_arrivals=variable.poisson(arrival_rate);
     for(int i=0; i<number_arrivals; i++)
        {
          Plane current_plane(flight_number++, current_time, arriving);
          if(small_airport.can_land(current_plane)!=success)
          current_plane.refuse( );
        }
     int number_departures = variable.poisson(departure_rate);
     for(int j=0; j<number_departures; j++)
        {
         Plane current_plane(flight_number++, current_time, departing);
         if(small_airport.can_depart(current_plane)!=success)
           current_plane.refuse( );
        }
     Plane moving_plane;
     switch(small_airport.activity(current_time, moving_plane))
      {
       case land: moving_plane.land(current_time); break;
       case flyingoff: moving_plane.fly(current_time); break;
       case idle: run_idle(current_time); 
      }
  }
  small_airport.shut_down(end_time);
}

void initialize(int &end_time, int &queue_limit,double &arrival_rate, double &departure_rate)
/* Pre: The user specifies the number of time units in the simulation, the maximal queue
         sizes permitted, and the expected arrival and departure_rates for the airport.
   Post: The program prints instructions and initializes the parameter send_time ,
         queue_limit ,arrival_rate , and departure_rate to the specified values.
   Uses: utility functionuser says yes */
{ 
  cout<<"This program simulates an airport with only one runway.\n";
  cout<<"One plane can land or depart in each unit of time.\n";
  cout<<"Up to what number of planes can be waiting to land";
  cout<<"or take off at any time? "<<flush;
  cin>>queue_limit;
  cout<<"How many units of time will the simulation run?\n";
  cin>>end_time;
  bool acceptable;
    do{
        cout<<"Expected number of arrivals per unit time?"<<flush;
        cin>>arrival_rate;
        cout<<"Expected number of departures per unit time?"<<flush;
        cin>>departure_rate;
        if(arrival_rate<0.0 || departure_rate<0.0)
           cerr<<"These_rates must be nonnegative." << endl;
        else acceptable=true;
        if(acceptable && arrival_rate+departure_rate>1.0)
           cerr<<"Safety Warning: This airport will become saturated.\n";
      }while(!acceptable);
}
void run_idle(int time)
{  cout<<time<<" Runway is idle\n"; }