算法学习(七)--链表之单链表

package com.tw.dst.link;

/**
 * <p>链表类</p>
 * @author tangw
 *
 */
public class Link {
	public int iData;
	public double dData;
	public Link next;
	
	public Link(int idata,double ddata){
		this.iData = idata;
		this.dData = ddata;
	}
	
	public void displayLink(){
		System.out.println(" idata="+iData+"  ddata:"+dData);
	}

}

 

package com.tw.dst.link;


/**
 * <p>单链表</p>
 * @author tangw 2010-11-29
 *
 */
public class LinkList {
	
	private Link first;//第一个链结点的引用

	public LinkList() {
		first = null;//引用类型初始化会自动赋值为null，此处不是必须的
	}
	//判断是否为空
	public boolean isEmpty(){
		return (first == null);
	}
	//插入数据
	public void insertFirst(int id,double dd){
		Link link = new Link(id,dd);
		link.next = first;
		first = link;
	}
	
	//删除数据
	public Link deleteFirst(){
		Link temp = first;
		first = first.next;
		return temp;	
	}
	//查找指定节点
	public Link find(int key){
		Link current = first;
		while( current.iData!=key ){
			if( current.next == null){
				return null;
			}else{
				current = current.next;//将当前对象的下一个引用置为当前
			}
		}
		return current;
	}
	
	//删除指定节点
	public Link delete(int key){
		Link current = first;	//存储当前对象
		Link previous = first;	//存储先前对象
		while(current.iData !=key ){
			if(current.next ==null){
				return null;
			}else{
				previous = current;
				current = current.next;
			}
		}
		if( current == first){
			first = first.next;
		}else{
			previous.next = current.next;
		}
		return current;
	}
	
	
	
	
	
	//输出链表数据
	public void displayList(){
		System.out.println("list (first-->last)");
		Link current = first;
		while(current!=null){
			current.displayLink();
			current =current.next;
		}
		System.out.println("");
	}
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		//----1---插入
		LinkList linkList = new LinkList();
		linkList.insertFirst(22, 2.99);
		linkList.insertFirst(44, 4.99);
		linkList.insertFirst(66, 6.99);
		
		linkList.displayList();
		//---2--删除
		/*while(!linkList.isEmpty()){
			Link aLink = linkList.deleteFirst();
			System.out.println("--deleted");
			aLink.displayLink();
		}
		
		linkList.displayList();*/
		
		//==3 查找=====
		Link link = linkList.find(44);
		if(null !=link){
			System.out.println("---idata:"+link.dData);
		}else{
			System.out.println("-find---no ");
		}
		
		//---4: 删除指定元素
		Link delLink = linkList.delete(44);
		if( null != delLink){
			System.out.println("----del link:"+delLink.dData);
		}else{
			System.out.println("-delete---no ");
		}
		linkList.displayList();
	}

}