Java 数据结构 单向链表简单实现

一、链表的基本结构

链表有很多种，比如单链表，双链表等等，链表是最基本的数据结构，其存储的你原理图如下图所示

上面展示的是一个单链表的存储原理图，简单易懂，head为头节点，他不存放任何的数据，只是充当一个指向链表中真正存放数据的第一个节点的作用，
而每个节点中都有一个next引用，指向下一个节点，就这样一节一节往下面记录，直到最后一个节点，其中的next指向null。目前实现单向链表。


二、简单代码实现

public class SimpleLink {

	public int    iData;
	public double dData;
	public SimpleLink next;
	
	public SimpleLink(int iData, double dData) {
		this.iData = iData;
		this.dData = dData;
	}
	
	public void displayLink(){
		System.out.print("{" + iData + ", " + dData + "}");
	}
}

class SimpleLinkList{
	
	private SimpleLink first;
	
	public SimpleLinkList(){
		first = null;
	}
	
	public boolean isEmpty(){
		return (first == null);
	}
	
	public void insertFirst(int id, double dd){
		SimpleLink newSimpleLink = new SimpleLink(id,dd);
		newSimpleLink.next = first;
		first = newSimpleLink;
		System.out.println("Insert " + id + ", " + dd + " to LinkList ");
	}
	
	public SimpleLink deleteFirst(){
		SimpleLink simpleLink = first;
		first = first.next;
		return simpleLink;
	}
	
	public void displayList(){
		System.out.println("List (first-->last): ");
		SimpleLink current = first;
		System.out.println("List struct display:"+JSON.toJSONString(first));
		while(current != null){
			current.displayLink();
			current = current.next;
		}
		System.out.println("  ");
	}
}

　　

编写测试类

public class SimpleLinkApp {
	
	public static void main(String[] args) {
		
		SimpleLinkList theList = new SimpleLinkList();
		
		theList.insertFirst(22, 2.99);
		theList.displayList();
		
		theList.insertFirst(44, 4.99);
		theList.displayList();
		
		theList.insertFirst(66, 6.99);
		theList.displayList();
		
		theList.insertFirst(88, 8.99);
		theList.displayList();
		
		theList.insertFirst(99, 9.99);
		theList.displayList();
		
		System.out.println("-----------------------delete-----------------------------------");
		while(!theList.isEmpty()){
			SimpleLink aLink = theList.deleteFirst();
			System.out.println("Deleted!");
			aLink.displayLink();
			System.out.println(" ");
			theList.displayList();
		}
	}
}

　　

输出结果

Insert 22, 2.99 to LinkList 
List (first-->last): 
List struct display:{"dData":2.99,"iData":22}
{22, 2.99}  
Insert 44, 4.99 to LinkList 
List (first-->last): 
List struct display:{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}
{44, 4.99}{22, 2.99}  
Insert 66, 6.99 to LinkList 
List (first-->last): 
List struct display:{"dData":6.99,"iData":66,"next":{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}}
{66, 6.99}{44, 4.99}{22, 2.99}  
Insert 88, 8.99 to LinkList 
List (first-->last): 
List struct display:{"dData":8.99,"iData":88,"next":{"dData":6.99,"iData":66,"next":{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}}}
{88, 8.99}{66, 6.99}{44, 4.99}{22, 2.99}  
Insert 99, 9.99 to LinkList 
List (first-->last): 
List struct display:{"dData":9.99,"iData":99,"next":{"dData":8.99,"iData":88,"next":{"dData":6.99,"iData":66,"next":{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}}}}
{99, 9.99}{88, 8.99}{66, 6.99}{44, 4.99}{22, 2.99}  
-----------------------delete-----------------------------------
Deleted!
{99, 9.99} 
List (first-->last): 
List struct display:{"dData":8.99,"iData":88,"next":{"dData":6.99,"iData":66,"next":{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}}}
{88, 8.99}{66, 6.99}{44, 4.99}{22, 2.99}  
Deleted!
{88, 8.99} 
List (first-->last): 
List struct display:{"dData":6.99,"iData":66,"next":{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}}
{66, 6.99}{44, 4.99}{22, 2.99}  
Deleted!
{66, 6.99} 
List (first-->last): 
List struct display:{"dData":4.99,"iData":44,"next":{"dData":2.99,"iData":22}}
{44, 4.99}{22, 2.99}  
Deleted!
{44, 4.99} 
List (first-->last): 
List struct display:{"dData":2.99,"iData":22}
{22, 2.99}  
Deleted!
{22, 2.99} 
List (first-->last): 
List struct display:null