我有一个相当复杂的（好吧，对我而言）程序应该在杂货店中模拟5行。 一个人上线，找到一个空的，然后继续结账。如果所有行都已满，则该人以最短的等待时间加入该行。 这个程序改编自我书中的另一个程序（因此所有评论）。 我能够只用2行就可以使用它，但有5行我无法正常工作。
// FILE: Carwash.java
// This program illustrates the use of the lineSimulate method which uses
// a simple queue to simulate cars waiting at a car wash.
import java.util.LinkedList;
import java.util.Queue;
import java.util.Scanner;
// import edu.colorado.simulations.BooleanSource;
// import edu.colorado.simulations.Line ;
// import edu.colorado.simulations.Averager;
/******************************************************************************
* The <CODE>CarWash</CODE> Java application illustrates the use of
* the <CODE>lineSimulate</CODE> method.
* The illustration uses the following values:
* <CODE>
* <br>lineTime = 240
* <br>arrivalTime = 0.0025
* <br>totalTime = 6000
* </CODE>
*
* <p><dt><b>Java Source Code for this class:</b><dd>
* <A HREF="../applications/CarWash.java">
* http://www.cs.colorado.edu/~main/applications/CarWash.java
* </A>
*
* @author Michael Main
* <A HREF="mailto:main@colorado.edu"> (main@colorado.edu) </A>
*
* @version
* Jun 12, 1998
******************************************************************************/
public class LineWait
{
/**
* The main method activates <CODE>lineSimulate</CODE> with the values:
* <CODE>
* <br>lineTime = 240
* <br>arrivalTime = 0.0025
* <br>totalTime = 6000
* </CODE>
* <BR>The <CODE>String</CODE> argument (<CODE>args</CODE>) is not used in
* this implementation.
**/
public static void main(String[ ] args)
{
final int LINETIME = 100 + (int)(Math.random() * ((400) + 1));
final double ARRIVALPROB = (Math.random() * ((.1) + 1));
final int TOTALTIME = 6000;
lineSimulate(LINETIME, ARRIVALPROB, TOTALTIME);
}
/**
* Simulate the running of a car washer for a specified amount of time.
* @param <CODE>lineTime</CODE>
* the number of seconds required to wash one car
* @param <CODE>arrivalProb</CODE>
* the probability of a customer arriving in any second, for example
* 0.1 is 10%
* @param <CODE>totalTime</CODE>
* the total number of seconds for the simulation
* <dt><b>Precondition:</b><dd>
* <CODE>lineTime</CODE> and <CODE>totalTime</CODE> are positive;
* <CODE>arrivalProb</CODE> lies in the range 0 to 1.
* <dt><b>Postcondition:</b><dd>
* The method has simulated a car wash where <CODE>lineTime</CODE> is the
* number of seconds needed to wash one car, <CODE>arrivalProb</CODE> is
* the probability of a customer arriving in any second, and
* <CODE>totalTime</CODE> is the total number of seconds for the
* simulation. Before the simulation, the method has written its three
* parameters to <CODE>System.out</CODE>. After the simulation, the method
* has written two pieces of information to <CODE>System.out</CODE>:
* (1) The number of cars washed, and (2) The average waiting time for
* customers that had their cars washed. (Customers that are still in the
* queue are not included in this average).
* @exception java.lang.IllegalArgumentException
* Indicates that one of the arguments violates the precondition.
**/
public static void lineSimulate
(int lineTime, double arrivalProb, int totalTime)
{
Queue<Integer> arrivalTimes = new LinkedList<Integer>( );
Queue<Integer> arrivalTimes2 = new LinkedList<Integer>( );
Queue<Integer> arrivalTimes3 = new LinkedList<Integer>( );
Queue<Integer> arrivalTimes4 = new LinkedList<Integer>( );
Queue<Integer> arrivalTimes5 = new LinkedList<Integer>( );
int next;
BooleanSource arrival = new BooleanSource(arrivalProb);
Line number = new Line(lineTime);
Line number2 = new Line(lineTime);
Line number3 = new Line(lineTime);
Line number4 = new Line(lineTime);
Line number5 = new Line(lineTime);
Averager waitTimes = new Averager( );
Averager waitTimes2 = new Averager();
Averager waitTimes3 = new Averager();
Averager waitTimes4 = new Averager();
Averager waitTimes5 = new Averager();
int currentSecond;
// Write the parameters to System.out.
System.out.println("Seconds to wait in line " + lineTime);
System.out.print("Probability of customer arrival during a second: ");
System.out.println(arrivalProb);
System.out.println("Total simulation seconds: " + totalTime);
// Check the precondition:
if (lineTime <= 0 || arrivalProb < 0 || arrivalProb > 1 || totalTime < 0)
throw new IllegalArgumentException("Values out of range");
//I BELIEVE THE PROBLEM IS BELOW THIS POINT
for (currentSecond = 0; currentSecond < totalTime; currentSecond++)
{ // Simulate the passage of one second of time.
// Check whether a new customer has arrived.
if (arrival.query( ))
{
//if(number.isBusy() && number2.isBusy() && number3.isBusy() && number4.isBusy() && number5.isBusy() )
//{
if(arrivalTimes.size() > arrivalTimes2.size() && arrivalTimes.size() > arrivalTimes3.size() && arrivalTimes.size() > arrivalTimes4.size() && arrivalTimes.size() > arrivalTimes5.size())
{
arrivalTimes.add(currentSecond);
System.out.println("Test");
}
else if(arrivalTimes2.size() > arrivalTimes.size() && arrivalTimes2.size() > arrivalTimes3.size() && arrivalTimes2.size() > arrivalTimes4.size() && arrivalTimes2.size() > arrivalTimes5.size())
{
arrivalTimes2.add(currentSecond);
System.out.println("Test");
}
else if(arrivalTimes3.size() > arrivalTimes.size() && arrivalTimes3.size() > arrivalTimes2.size() && arrivalTimes3.size() > arrivalTimes4.size() && arrivalTimes3.size() > arrivalTimes5.size())
{
arrivalTimes3.add(currentSecond);
System.out.println("Test");
}
else if(arrivalTimes4.size() > arrivalTimes.size() && arrivalTimes4.size() > arrivalTimes3.size() && arrivalTimes4.size() > arrivalTimes2.size() && arrivalTimes4.size() > arrivalTimes5.size())
{
arrivalTimes4.add(currentSecond);
System.out.println("Test");
}
else{arrivalTimes5.add(currentSecond);}
//}
}
// Check whether we can put the person into a line.
if ((!number.isBusy( )) && (!arrivalTimes.isEmpty( )))
{
next = arrivalTimes.remove( );
waitTimes.addNumber(currentSecond - next);
number.startMoving( );
}
if ((!number2.isBusy( )) && (!arrivalTimes2.isEmpty( )))
{
next = arrivalTimes2.remove( );
waitTimes2.addNumber(currentSecond - next);
number2.startMoving( );
}
if ((!number3.isBusy( )) && (!arrivalTimes2.isEmpty( )))
{
next = arrivalTimes2.remove( );
waitTimes3.addNumber(currentSecond - next);
number3.startMoving( );
}
if ((!number4.isBusy( )) && (!arrivalTimes2.isEmpty( )))
{
next = arrivalTimes2.remove( );
waitTimes4.addNumber(currentSecond - next);
number4.startMoving( );
}
if ((!number5.isBusy( )) && (!arrivalTimes2.isEmpty( )))
{
next = arrivalTimes2.remove( );
waitTimes5.addNumber(currentSecond - next);
number5.startMoving( );
}
// Subtract one second from the remaining time in the current li
number.reduceRemainingTime( );
number2.reduceRemainingTime( );
number3.reduceRemainingTime( );
number4.reduceRemainingTime( );
number5.reduceRemainingTime( );
}
//I BELIEVE THE PROBLEM IS ABOVE THIS POINT
// Write the summary information about the simulation.
System.out.println("\nCustomers served Line1: " + waitTimes.howManyNumbers( ));
if (waitTimes.howManyNumbers( ) > 0)
System.out.println("Average wait Line1: " + waitTimes.average( ) + " sec");
System.out.println("\nCustomers served Line2: " + waitTimes2.howManyNumbers( ));
if (waitTimes.howManyNumbers( ) > 0)
System.out.println("Average wait Line2: " + waitTimes2.average( ) + " sec");
System.out.println("\nCustomers served Line3: " + waitTimes3.howManyNumbers( ));
if (waitTimes.howManyNumbers( ) > 0)
System.out.println("Average wait Line3: " + waitTimes3.average( ) + " sec");
System.out.println("\nCustomers served Line4: " + waitTimes4.howManyNumbers( ));
if (waitTimes.howManyNumbers( ) > 0)
System.out.println("Average wait Line4: " + waitTimes4.average( ) + " sec");
System.out.println("\nCustomers served Line5: " + waitTimes5.howManyNumbers( ));
if (waitTimes.howManyNumbers( ) > 0)
System.out.println("Average wait Line5: " + waitTimes5.average( ) + " sec");
}
}
答案 0 :(得分：4)
这里看起来像是典型的复制粘贴错误：
if ((!number3.isBusy( )) && (!arrivalTimes**2**.isEmpty( )))
...
if ((!number4.isBusy( )) && (!arrivalTimes**2**.isEmpty( )))
...
if ((!number5.isBusy( )) && (!arrivalTimes**2**.isEmpty( )))
...
正如Ozan所说，如果您有多个项目，请使用一些列表或数组，这样可以减少您犯这样错误的几率。
编辑：其他建议，我认为您应该使用＆gt; =而不是＆gt;当比较到达时间时，如果你有超过1个最大值，你可能最终得到一个非最佳值，即如果你有2个，2个，1个，1个，你将最终将客户放到行上5，即使你可能想把它放到第1行或第2行。
答案 1 :(得分：2)
任何大于1的项目数应在列表中处理：
List<Queue<Integer>> queues = new ArrayList<Queue<Integer>>();
for (int i=1; i<=5; i++)
queues.add(new LinkedList<Integer>>());
开始设计更接近规范的代码：
Queue<Integer> emptyqueue = GetEmptyQueue(queues);
if (emptyqueue != null)
...
else
...