Java更新一個唯一變量的問題，模擬1行1隊列

Question

我遇到了一個變量沒有更新的問題，當它應該。我也不確定在哪裏更新這個變量，因爲它不適合我的代碼中的任何if語句測試。你必須知道，我需要的全部變量是變量peopleCompleted得到更新時第一個人進入完成。在我的代碼中，您會看到這個第一個人到達的位置，將他的位置作爲curServed，然後打印出來而不被添加到隊列中，其他人排隊。您會注意到curServed在serviceComplete()中發生了變化，因爲它處理其他所有人在隊列中。以下是我的代碼和相同的輸出，因爲peopleCompleted未針對該第一人進行更新，所以這是不正確的。基本上，我真的需要幫助，知道在哪裏更新他的完成。這是一個單線隊列的模擬。我是一個初學者/學生

CODE

public boolean arrival() 
    { 
    Customer myCust = new Customer(curTime); 
    if(curServed == null) // If no one being served 
    { 
     curServed = myCust; // myCust is served 
     peopleNoWait++; 
     return true; 
    } 
    else if(!q.isFull()) 
    { 
     q.add(myCust); 
     peopleThatHadToWait++; 
     return true; 
    } 
    return false; 
    } 

    public Customer serviceComplete() 
    { 
    if(q.isEmpty()) 
    { 
     curServed = null; 
    } 
    else 
    { 
     curServed = q.remove(); // Remove next from customer queue 
     peopleCompleted++; 
     sumOfWaitTime += getWaitTime(); 
    } 
    return curServed; 
    } 

THESE BELOW了處理上述

private void doArrival() 
    { 
     boolean check = sim.arrival(); // Do an arrival 
     if(check == false) 
     System.out.println("Customer arrived but left immediately" 
       + " because the line was full (too long) at time " + 
       sim.getTime() + "."); 
     else 
     System.out.println("A customer entered system at time " + 
       sim.getTime() + "." + " Number waiting in queue is " 
       + sim.getNumWaiting() + "."); 
    } 

    private void doServiceComplete() 
    { 
     if(sim.notBeingServed() == true) 
     { 
     System.out.println("No customer is being served at the present time" 
       + " of " + sim.getTime() + "."); 
     } 
     else 
     { 
     System.out.print("Customer " + sim.getCurCust().toString() + 
       " finished at time " + sim.getTime() + ". Number waiting" + 
       " is "); 
     System.out.println(sim.getNumWaiting() + "."); 
     } 
     sim.serviceComplete(); 

方法模擬返回下面的丘壑

public int getNumWaiting() 
    { 
    int total = peopleThatHadToWait - peopleCompleted; 
    return total; 
    } 

    public int getTotalServed() 
    { 
    return peopleCompleted; 
    } 

示例輸出，其中的錯誤是：

1. 客戶C1/T2結束在時間7編號的等待是2 //應該是1

2. 客戶C2/T6結束在時間7。數等待是1 //應該是0

3. 客戶C3/T7結束在時間13號等待是5 // 4

4. 客戶C4/T7 FINI在時間棚16號等待是4 //等

5. 客戶C5/T8結束在時間16號等待是3.

6. 客戶C6/T8結束在時間17號等待是2 。

7. 客戶C7/T9結束時刻17號等待是1

8. 的人數擔任爲7 //應該是8

9. 人SERV數ED是7 //應該是8個

評論：

這些都是造成問題的線路。等待的人數和 服務的人數是不正確的。這是因爲（）的缺乏 的他完成後peopleCompleted正在與第一人稱更新，這 根據您的意見，是不是在serviceComplete做

Answer 1

我懷疑這是因爲這裏的代碼塊。

private void doServiceComplete() 
{ 
    if(sim.notBeingServed() == true) 
    { 
    System.out.println("No customer is being served at the present time" 
      + " of " + sim.getTime() + "."); 
    } 
    else 
    { 
    System.out.print("Customer " + sim.getCurCust().toString() + 
      " finished at time " + sim.getTime() + ". Number waiting" + 
      " is "); 
    System.out.println(sim.getNumWaiting() + "."); 
    } 
    sim.serviceComplete(); 
} 

當你到sim.getNumWaiting()你的人在等待將比你期望的少一個。 sim.serviceComplete()有peopleCompleted++這是您打印結果後執行。在調用sim.getNumWaiting()之前，您應該將此移至方法的開頭或其他邏輯位置。

例子：

private void doServiceComplete() 
{ 
    sim.serviceComplete(); 

    if(sim.notBeingServed() == true) 
    { 
    System.out.println("No customer is being served at the present time" 
      + " of " + sim.getTime() + "."); 
    } 
    else 
    { 
    System.out.print("Customer " + sim.getCurCust().toString() + 
      " finished at time " + sim.getTime() + ". Number waiting" + 
      " is "); 
    System.out.println(sim.getNumWaiting() + "."); 
    } 
}