5.单链表

public class Link {
　　　　 //链结点的数据
	public int iData;
	public int dData;
　　　　　　//链结点指向下个结点的地址引用变量
	public Link next;
	public Link(int iData,int dData){
		this.iData=iData;
		this.dData=dData;
	}
	public void displayLink(){
		System.out.println("{"+this.iData+","+this.dData+"}");
	}
	
}

public class LinkList {
    　　//存储头结点的地址
	private Link first;
	public LinkList(){
		this.first=null;
	}
　　　　　
	public boolean isEmpty(){
		return this.first==null;
	}
　　　　 
	public void insertFirst(int iData,int dData){
		Link newFirst=new Link(iData, dData);
		newFirst.next=this.first;
		this.first=newFirst;
		
	}
	public Link deleteFirst(){
		Link temp=this.first;
		this.first=this.first.next;
		return temp;
	}
	public void displayLinkList(){
		Link current=this.first;
		while(current!=null){
			current.displayLink();
			current=current.next;
		}
	}
	public Link find(int key){
		Link current =this.first;
		while(key!=current.iData){
			if(current.next==null){
				return null;
			}else{
				current=current.next;
			}
		}
		
		return current;
	}
	public Link delete(int key){
		Link current=this.first;
		Link previous=this.first;
		while(current.iData!=key){
			if(current.next==null){
				return null;
			}else{
				previous=current;
				current=current.next;
			}
		}
		if(current==this.first){
			this.first=this.first.next;
		}else{
			previous.next=current.next;
		}
		return current;
	}
}