創建不確定數量的對象來放入一個deque

Question

我想創建一個用戶定義的雙向存儲用戶定義的金額對象。我創建一個項目對象，並給它的值或項目＃和價格，而不是將對象存儲在雙端隊列中。到目前爲止，我的主要由一個單一的項目組成。每次我設置該項目時，都會將先前存儲的項目值寫入最近的項目中。我如何去創造一個數量不定的項目來存儲它們全部？

主要

import java.*; 
import java.util.*; 

public class MyDequeApp { 

public static void main(String[] args) 
{ 
    //variables 
    String userinNum; 
    double userinPrice; 
    int queOp; 

    //creating new Item 
    Item item1= new Item(); 

    //creating new Scanner  
    Scanner scan1=new Scanner(System.in); 

    //user input number of elements in the deque 
    System.out.println("Enter the number of elements in the que"); 
    int queElm=scan1.nextInt();  
    MyDeque theQueue=new MyDeque(queElm); 

    //do/while so while user selects 1-7 they stay in the switch/case 
    do 
    { 
     //switch/case menu 
     System.out.println("1. Insert to front"); 
     System.out.println("2. Insert to rear"); 
     System.out.println("3. Remove from front"); 
     System.out.println("4. Remove from rear"); 
     System.out.println("5. Peek front"); 
     System.out.println("6. Peek rear"); 
     System.out.println("7. Display deque"); 
     System.out.println("Anything else to Quit"); 

     //user input the case number 
     queOp=scan1.nextInt(); 
     scan1.nextLine(); 

     switch(queOp) 
     { 
      //insert to front 
      case 1: 
       System.out.println("Enter an item number"); 
       userinNum=scan1.nextLine(); 
       item1.setNum(userinNum); 
       System.out.println("Enter a price"); 
       userinPrice=scan1.nextDouble(); 
       scan1.nextLine(); 
       item1.setPrice(userinPrice); 
       System.out.println(item1.toString()); 
       theQueue.insertFront(item1); 
        break; 

      //insert to rear 
      case 2: 
       System.out.println("Enter an item numbeR"); 
       userinNum=scan1.nextLine(); 
       item1.setNum(userinNum); 
       System.out.println("Enter a pricE"); 
       userinPrice=scan1.nextDouble(); 
       scan1.nextLine(); 
       item1.setPrice(userinPrice); 
       System.out.println(item1.toString()); 
       theQueue.insertFront(item1); 
       theQueue.insertRear(item1); 
        break; 

      //remove from front 
      case 3: 
       theQueue.removeFront(); 
        break; 

      //remove from rear 
      case 4: 
       theQueue.removeRear(); 
        break; 

      //peek front 
      case 5: 
       System.out.println(theQueue.peekFront()); 
        break; 

      //peek rear 
      case 6: 
       System.out.println(theQueue.peekRear()); 
        break; 

      //display the deque 
      case 7: 
       System.out.println(theQueue.toString()); 
        break; 

      //quit 
      default: 
        break; 


     } 

    }while(queOp>0 && queOp<8); 

} 

}

Answer 1

你需要添加

item1= new Item(); 

你一個既完成後，並將它添加到您的隊列中，或在一個地方在你輸入新數據之前，否則程序會認爲item1總是相同的項目。