scheduler.cpp

这是C＋＋编程经典的书上实例的源代码。 （英文名是《C＋＋ how to program》第3版）

// scheduler.cpp
// Member function definitions for class Scheduler.
#include <iostream>

using std::cout;
using std::endl;

#include <cstdlib>
#include <ctime>

#include "scheduler.h"
#include "floor.h"
#include "person.h"

// constructor
Scheduler::Scheduler( Floor &firstFloor, Floor &secondFloor )   
   : currentClockTime( 0 ), floor1Ref( firstFloor ),
     floor2Ref( secondFloor )
{
   srand( time( 0 ) ); // seed random number generator
   cout << "scheduler created" << endl;

   // schedule first arrivals for floor 1 and floor 2
   scheduleTime( floor1Ref );
   scheduleTime( floor2Ref );
}


Scheduler::~Scheduler() // destructor
{ cout << "scheduler destroyed" << endl; }

// schedule arrival on a floor
void Scheduler::scheduleTime( const Floor &floor )
{
   int floorNumber = floor.getNumber();
   int arrivalTime = currentClockTime + ( 5 + rand() % 16 );

   floorNumber == Floor::FLOOR1 ?
      floor1ArrivalTime = arrivalTime : 
      floor2ArrivalTime = arrivalTime;

   cout << "(scheduler schedules next person for floor " 
        << floorNumber << " at time " << arrivalTime << ')'
        << endl;
}

// reschedule an arrival on a floor
void Scheduler::delayTime( const Floor &floor )
{
   int floorNumber = floor.getNumber();

   int arrivalTime = ( floorNumber == Floor::FLOOR1 ) ? 
      ++floor1ArrivalTime : ++floor2ArrivalTime;

   cout << "(scheduler delays next person for floor "
        << floorNumber << " until time " << arrivalTime << ')'
        << endl;
}

// give time to scheduler
void Scheduler::processTime( int time )
{
   currentClockTime = time;   // record time
   
   // handle arrivals on floor 1
   handleArrivals( floor1Ref, currentClockTime );

   // handle arrivals on floor 2
   handleArrivals( floor2Ref, currentClockTime );
}

// create new person and place it on specified floor
void Scheduler::createNewPerson( Floor &floor )
{
   int destinationFloor = 
      floor.getNumber() == Floor::FLOOR1 ?
         Floor::FLOOR2 : Floor::FLOOR1;

   // create new person
   Person *newPersonPtr = new Person( destinationFloor );

   cout << "scheduler creates person " 
        << newPersonPtr->getID() << endl;
   
   // place person on proper floor
   newPersonPtr->stepOntoFloor( floor );
   
   scheduleTime( floor ); // schedule next arrival
}

// handle arrivals for a specified floor
void Scheduler::handleArrivals( Floor &floor, int time )
{
   int floorNumber = floor.getNumber();

   int arrivalTime = ( floorNumber == Floor::FLOOR1 ) ? 
      floor1ArrivalTime : floor2ArrivalTime;

   if ( arrivalTime == time ) {
      
      if ( floor.isOccupied() ) // see if floor occupied
         delayTime( floor );
      else
         createNewPerson( floor );
   }
}

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 * (C) Copyright 2000 by Deitel & Associates, Inc. and Prentice Hall.     *
 * All Rights Reserved.                                                   *
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