鏈接列表（循環）

Question

我在爲鏈接列表做循環時遇到了麻煩。 我想嘗試從用戶輸入ID和名稱，但似乎最後輸入的細節正在覆蓋整個鏈接的事情。但是當我使用實例(myLinkedList.insertFirstLink("name", id))，它確實有效。

這裏是我的代碼..

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

    class Example 
    { 
     public static int ID; 
     public static int ans; 
     public static String name; 
     public Example next; 

     public Example(int ID, String name) 
     { 
      this.ID = ID; 
      this.name = name; 
     } 

     public void display() 
     { 
      System.out.println("ID: "+ID + " - " + name); 
     } 

     public String toString() 
     { 
      return name; 
     } 

     public static void main(String args[]) throws IOException 
     { 
      BufferedReader inpt = new BufferedReader(new InputStreamReader (System.in)); 

      int x = 0; 
      LinkList myLinkedList = new LinkList(); 

      while(x<=2) 
      { 
      System.out.print("Enter Name: "); 
      name = inpt.readLine(); 

      System.out.print("Input ID#: "); 
      ID = Integer.parseInt(inpt.readLine()); 

      System.out.println(); 

      myLinkedList.insertFirstLink(name, ID); 
      x++; 
      } 

     /* myLinkedList.insertFirstLink("Vishera", 2341); 
      myLinkedList.insertFirstLink("Bulldozer", 1234); 
      myLinkedList.insertFirstLink("Allendale", 3214); 
      myLinkedList.insertFirstLink("Wolfdale", 4312); */ 

      myLinkedList.displayLink(); 

     } 
    } 

    class LinkList 
    { 
     public Example head; 
     public Example tail; 

     public LinkList() 
     { 
      head = null; 
      tail = head; 
     } 

     public boolean isEmpty() 
     { 
      return(head == null); 
     } 

     public void insertFirstLink(String name, int ID) 
     { 
      Example newLink = new Example(ID, name); 
      if(head==null) 
      { 
       head = newLink; 
       tail = head; 
      } 
      else 
      { 
       tail.next = newLink; 
       tail = newLink; 
      } 
     } 

     public void displayLink() 
     { 
      Example theLink = head; 

      while(theLink != null) 
      { 
       theLink.display(); 

       System.out.println("The Next Link: " + theLink.next); 

       theLink = theLink.next; 

       System.out.println(); 

      } 
     } 
    } 

謝謝！

Answer 1

。在你Example class

首先，你還沒有創建實例變量和使用靜態創建類變量，所有的問題。爲creating instance variable只能使用private關鍵字。

Corrected Code

public class Example { 
private int ID; 
private int ans; 
private String name; 
public Example next; 

public Example(int ID, String name) { 
    this.ID = ID; 
    this.name = name; 
} 

public void display() { 
    System.out.println("ID: " + ID + " - " + name); 
} 

public static void main(String args[]) throws IOException { 
    int userId; 
    String userName; 
    BufferedReader inpt = new BufferedReader(new InputStreamReader(
      System.in)); 

    int x = 0; 
    LinkList myLinkedList = new LinkList(); 

    while (x <= 2) { 
     System.out.print("Enter Name: "); 
     userName = inpt.readLine(); 

     System.out.print("Input ID#: "); 
     userId = Integer.parseInt(inpt.readLine()); 

     System.out.println(); 

     myLinkedList.insertFirstLink(userName, userId); 
     x++; 
    } 

    /* 
    * myLinkedList.insertFirstLink("Vishera", 2341); 
    * myLinkedList.insertFirstLink("Bulldozer", 1234); 
    * myLinkedList.insertFirstLink("Allendale", 3214); 
    * myLinkedList.insertFirstLink("Wolfdale", 4312); 
    */ 

    myLinkedList.displayLink(); 

} 

public String toString() { 
    return name; 
} 

} 

class LinkList { 
public Example head; 
public Example tail; 

public LinkList() { 
    head = null; 
    tail = head; 
} 

public boolean isEmpty() { 
    return (head == null); 
} 

public void insertFirstLink(String name, int ID) { 
    Example newLink = new Example(ID, name); 
    if (head == null) { 
     head = newLink; 
     tail = newLink; 
    } else { 
     tail.next = newLink; 
     tail = newLink; 
    } 
} 

public void displayLink() { 
    Example theLink = head; 

    while (theLink != null) { 
     theLink.display(); 

     System.out.println("The Next Link: " + theLink.next); 

     theLink = theLink.next; 

     System.out.println(); 

    } 
} 
} 

做出上述更改後，

輸出

Enter Name: a 
Input ID#: 1 

Enter Name: b 
Input ID#: 2 

Enter Name: c 
Input ID#: 3 

ID: 1 - a 
The Next Link: b 

ID: 2 - b 
The Next Link: c 

ID: 3 - c 
The Next Link: null