将随机数分配给不同的对象

Question

I have a function that generates numbers randomly using Poisson's Distribution and I have a Bus class and a Bus Stop class as well. Now I have generated 5 bus objects and 15 bus stop objects. My goal here is to assign random numbers to these five bus objects to indicate their bus stop positions.

private static int getPoissonRandom(double mean){
Random r = new Random();
double L = Math.exp(-mean);
int k = 0;
double p = 1.0;
do {
    p = p * r.nextDouble();
    k++;
} while (p > L);
return k - 1;
}

Bus Stop Class

public class busStop {
int bus_stop_id;
public busStop(){    
  this.bus_stop_id=bus_stop_id;
} 
public void create_busStop(int total,int position){
   for(int i=1; i<=total; i++){
        bus_stop_id=i;
        //System.out.println("Bus_Stop with ID:"+i+" Spawned");
        setBusPosition(i,position);
    }
}
public void setBusPosition(int bus_id, int stop_id){
    System.out.println("Bus : "+bus_id+ " at Stop :"+stop_id);
    }
 }

Bus class

public class Bus {
int capacity;
int bus_id=0;



public Bus(){
  this.capacity=50;    
  this.bus_id=bus_id;
} 

public void spawn_bus(int bus_total){
    for(int i=1; i<=bus_total; i++){
        bus_id=i;
        System.out.println("Bus with ID:"+i+" created");
    }
}   

}

Main Function

    public static void main(String[] args) {
  int bus_number=5;  
  int total_bus_stops=15; 
  Bus bus = new Bus();
 busStop stops = new busStop();
 getPoissonRandom(5);
 bus.spawn_bus(bus_number);
 stops.create_busStop(total_bus_stops,getPoissonRandom(5));

}

when I run the code, I keep getting one number assigned to all 5 bus objects, but I want different random numbers using Poisson Distribution generator to be assigned to the 5 bus objects

Answer 1

you are facing this problem since you have called the random generation method once only. To achieve the desired output you need to call getPoissonRandom(double mean) inside create_busStopMethod something like that:

    public void create_busStop(int total,int position){
   for(int i=1; i<=total; i++){
        bus_stop_id=i;
        //System.out.println("Bus_Stop with ID:"+i+" Spawned");
        setBusPosition(i,MainClass.getPoissonRandom(position));
    }
}

and then call the method as

stops.create_busStop(total_bus_stops,5);

or you can modify creat_busStop to accept id and position rather than total_bus_stops as follows:

public void create_busStop(int id,int position){
    bus_stop_id=id;
    setBusPosition(id,position);
}

}

and then call the method within for loop as

for(int i=0;i<total_bus_stops;i++){
stops.create_busStop(i,getPoissonRandom(5));
}