链表，搜索

Question

我的老师给了我们一个处理链接列表的练习作业，我得到了搜索和搜索助手的代码，但我在实际初始化搜索时遇到了麻烦。我该怎么办呢？我尝试提示用户输入一个变量，然后通过搜索方法抛出该变量，但出现错误“List_3 类型中的方法 search(T) 不适用于参数（整数）”

该程序必须：创建一个链接列表，提示用户输入要搜索的值，使用递归搜索链接列表对象以查找指定值的方法搜索。如果找到该值，该方法应返回对该值的引用；否则，它应该返回 null。

 import java.util.Scanner;


class ListNode< T > 
{
   T data; 
   ListNode< T > nextNode;


   ListNode( T object ) 
   { 
      this( object, null ); 
   } 

   ListNode( T object, ListNode< T > node )
   {
      data = object;    
      nextNode = node;  
   } 


   T getData() 
   { 
      return data; 
   } 


   ListNode< T > getNext() 
   { 
      return nextNode;
   } 
} 


public class List_3< T >
{
   private ListNode< T > firstNode;
   private ListNode< T > lastNode;
   private String name; 

   public static void main( String[] args )
   {
      Scanner scan = new Scanner(System.in);
      int result;
      List_3< Character > list1 = new List_3< Character >();
      Integer number;

      list1.insertAtFront( '3' );
      list1.insertAtFront( '4' );
      list1.insertAtBack( '5' );
      list1.insertAtBack( '6' );
      list1.insertAtFront( '2' );
      list1.insertAtFront( '1' );
      list1.insertAtBack( '7' );
      list1.insertAtBack( '8' );
      list1.insertAtFront( '0' );
      list1.insertAtBack( '9' );

      list1.print();
      System.out.println("Please enter a value to search for: ");
      number = scan.nextInt();
      result = search(number);
   }

   public List_3() 
   { 
      this( "list" ); 
   } 


   public List_3( String listName )
   {
      name = listName;
      firstNode = lastNode = null;
   } 


   public void insertAtFront( T insertItem )
   {
      if ( isEmpty() ) 
         firstNode = lastNode = new ListNode< T >( insertItem );
      else
         firstNode = new ListNode< T >( insertItem, firstNode );
   } 


   public void insertAtBack( T insertItem )
   {
      if ( isEmpty() )
         firstNode = lastNode = new ListNode< T >( insertItem );
      else
         lastNode = lastNode.nextNode = new ListNode< T >( insertItem );
   } 


   public T removeFromFront() throws EmptyListException
   {
      if ( isEmpty() ) 
         throw new EmptyListException( name );

      T removedItem = firstNode.data; 


      if ( firstNode == lastNode )
         firstNode = lastNode = null;
      else
         firstNode = firstNode.nextNode;

      return removedItem; 
   }


   public T removeFromBack() throws EmptyListException
   {
      if ( isEmpty() ) 
         throw new EmptyListException( name );

      T removedItem = lastNode.data; 


      if ( firstNode == lastNode )
         firstNode = lastNode = null;
      else 
      { 
         ListNode< T > current = firstNode;


         while ( current.nextNode != lastNode )
            current = current.nextNode;

         lastNode = current; 
         current.nextNode = null;
      } 

      return removedItem; 
   } 

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

   public void print()
   {
      if ( isEmpty() ) 
      {
         System.out.printf( "Empty %s\n", name );
         return;
      } 

      System.out.printf( "The %s is: ", name );
      ListNode< T > current = firstNode;


      while ( current != null ) 
      {
         System.out.printf( "%s ", current.data );
         current = current.nextNode;
      } 

      System.out.println();
   } 


   public T search( T input )
   {
      return searchHelper( input, firstNode );
   } // end method search


   private T searchHelper( T input, ListNode< T > node )
   {
      if ( node == null )
         return null;
      else if ( node.getData().equals( input ) )
         return node.getData();
      else
         return searchHelper( input, node.getNext() );
   }

} 

Answer 1

你把整数和字符搞混了。决定您的列表是什么：List 或 List（或 List

'1'.equals(1) =>;假的

祝你好运！