arrivalgen.h

c++写的实现数学排队论的算法程序

#ifndef ARRIVALGEN_H
#define ARRIVALGEN_H

#include <cstdlib>  
#include <math.h>     
//class invariant for the arrivalGenerator class:

//An arrivalGenerator object generates the number of the next person arriving
//  for service, if there is one.  Whether or not a person arrives is
//  determined at random according to a set probability.

//The arrivalGenerator object contains:
//  1)  The probability that is used to determine if an arrival occurs.
//  2)  The number of the next arrival, as an identifier for that person.
//The srand function takes an int number as a seed. It uses the seed to generate a long sequence of (pseudo) random numbers between 0 and a large maximum called MAX_RAND. Since srand sets up a whole sequence of numbers, the program should not call srand more than once. 
//The rand() function actually returns the next number in the random sequence. Use rand () wherever you need a random number  
class arrivalGenerator
{
public:
    arrivalGenerator (int s, double P,int intertime)
	{
     srand (s);             //seed the random sequence
   
     probability   = P;
     nextCustomer  = -1;
//	 timer = 0;
	 inter = intertime;
	}

        
   bool isArrival (int arrivetime)
   {
    bool returnVal = false;
       
 //   double event = rand () % 100 + 1;   //Get a random number betw 
                                       //  1 and 100
       
 //   if (event / 100.0 <probability)   //Determine if an arrival
                                       //  occurred
 //   {   // timer++;
		//if(timer== inter){	
         returnVal = true;
         nextCustomer++;
         arrivaldate[nextCustomer] = arrivetime;
//		 timer=0;
		//}
 //   }
          
    return returnVal;
   }
   
   int Duree_entre_deux_arrive()
   {
	  double returnval;
	  returnval = (double) (-log(1.0 - (double)((rand() % 100) / 100.0))*inter);
      if(returnval<0.5) return(0);
	  else if(returnval<1.0) return(1);
      else return((int)returnval);    
   }

   double getpropale(){
     double propa = rand() % 101;
	 return( propa/100.0);
   }
     
    int getArrival ()
	{
     return nextCustomer;
	}

	int getarrivetime(int numcustomer){
	  return arrivaldate[numcustomer];
	}

	void cleararrivetime(int numcustomer){
	   arrivaldate[numcustomer] = -1;
	}
           
private:
    double probability;
    int    nextCustomer;
//	int    timer ;
	int    inter;
	int    arrivaldate[MAXSIZE];
};
      
#endif