リンクされたリストとイテレータ

Question

everyone。特定の食材を使ってサンドイッチを作る必要があり、特定のトッピングを挿入するにはリンクされたリストのいくつかの要素の間を反復する必要があります。チキンとトマトの間にベーコンを入れなければならないコードの最後の2つの部分について助けが必要です。何らかの理由で、ベーコンは塩とBread2の間の最後に現れています。どんな助けでも大歓迎です。あなたの時間をありがとう。

/* 
Programmer: Yamin Mousselli 
Date: 03/27/2016 
Purpose: Demonstrate Use and Knowledge of LinkedList and Iterator. You CAN'T use an index number for inserting elements into 
linked list. You must only use the list iterator. Submit one java file only. 
*/ 
import java.util.List; 
import java.util.LinkedList; 
import java.util.ListIterator; 

public class LinkedListDemo { 
    public static void main(String[] args) 
    { 

    List<String> myLinkedList = new LinkedList<String>(); 

    String strOutput=""; 

    //BUILD THE SANDWICH 

    myLinkedList.add("Bread1"); 
    myLinkedList.add("mustard"); 
    myLinkedList.add("lettuce"); 
    myLinkedList.add("chicken"); 
    myLinkedList.add("tomato"); 
    myLinkedList.add("Bread2"); 

    ListIterator<String> lit = myLinkedList.listIterator(); 

    while(lit.hasNext()) 
    { 
     strOutput += (lit.next().toString() + ",") ; 
    } 
    strOutput +=("You have reached the end of the sandwich.\n"); 


    //SHOW THE CURRENT SANDWICH IN REVERSE USING "PREVIOUS()" METHOD 
    while(lit.hasPrevious()) 
    { 
     strOutput += (lit.previous().toString() + ","); 
    } 
    strOutput +=("You have reached the end of the sandwich.\n"); 


    //ADD PICKLES BETWEEN LETTUCE AND CHICKEN 
    while(lit.hasNext()) 
    { 
     if(lit.next().toString().equals("lettuce")) 
     { 
      lit.add("pickles"); 
      break; 
     } 
    } 

    while(lit.hasPrevious()) 
    { 
     lit.previous(); 
    } 

    while(lit.hasNext()) 
    { 
     strOutput += (lit.next().toString() + ",") ; 
    } 
    strOutput +=("You have reached the end of the sandwich.\n"); 


    //ADD CHEESE BETWEEN TOMATO AND BREAD2 
    while(lit.hasPrevious()) 
    { 
     if(lit.previous().toString().equals("Bread2")) 
     { 
      lit.add("cheese"); 
      break; 
     } 
    } 

    while(lit.hasPrevious()) 
    { 
     lit.previous(); 
    } 

    while(lit.hasNext()) 
    { 
     strOutput += (lit.next().toString() + ","); 
    } 
    strOutput += ("You have the reached the end of the sandwich.\n"); 


    //ADD SALT BETWEEN CHEESE AND BREAD2 
    while(lit.hasPrevious()) 
    { 
     if(lit.previous().toString().equals("Bread2")) 
     { 
      lit.add("salt"); 
      break; 
     } 
    } 

    while(lit.hasPrevious()) 
    { 
     lit.previous(); 
    } 

    while(lit.hasNext()) 
    { 
     strOutput += (lit.next().toString() + ","); 
    } 
    strOutput += ("You have the reached the end of the sandwich.\n"); 


    //GO BACKWARDS AND INSERT BACON BETWEEN CHICKEN AND TOMATO 
    while(lit.hasPrevious())  
    { 
     if(lit.previous().toString().equals("chicken")); 
     { 
      lit.add("bacon"); 
      break; 
     } 
    } 

    while(lit.hasPrevious()) 
    { 
     lit.previous(); 
    } 

    while(lit.hasNext()) 
    { 
     strOutput += (lit.next().toString() + ","); 
    } 
    strOutput += ("You have the reached the end of the sandwich.\n"); 


    //SHOW FINAL SANDWICH IN FORWARD ORDER 

    javax.swing.JOptionPane.showMessageDialog(null, strOutput); 
    System.exit(0); 
    } 

} 

Answer 1

あなたはタイプミスがあります

if(lit.previous().toString().equals("chicken")); // <-- semi-colon 
    { 
     lit.add("bacon"); 
     break; 
    } 

EDIT：

セミコロンは、早期にif文を閉じます。つまり、if文に関係なく、lit.add("bacon");が常に実行されます。