用Java实现单链表的基本操作

package mars;

//单链表添加，删除节点
public class ListNode {
    
    private Node head;
    
    public ListNode(){
        head=null;
    }
    //在链表前添加节点
    public void addpre(int dvalue){
        Node n=new Node(dvalue);
        
        if(head==null){
            head=n;
        }else{
            n.next=head;
            head=n;
        }
        
    }
    //在链表后添加节点
    public void add(int dvalue){
        Node n=new Node(dvalue);
        Node current = head;  
        while(current!=null){
            if(current.next==null){
                current.next=n;
                return;
            }
            current=current.next;
        }
        
    }
    //删除值为dvalue的节点
    public Node delete(int dvalue){
        Node current=head;
        if(head.value==dvalue){
            head=head.next;
            return current;
        }
        while(current.next!=null){
            if(current.next.value==dvalue){
                Node temp=current.next;
                current.next=temp.next;
                return temp;
            }
            current=current.next;
        }
        return null;
    }
    //删除特定位置的节点
    public Node deletepos(int pos){
        Node current=head;
        int counter=0;
        if(pos==0){
            head=head.next;
            return current;
        }
        while(current!=null){
            if((counter==(pos-1))&&(current.next!=null)){
                Node temp=current.next;
                current.next=temp.next;
                return temp;
            }
            current=current.next;
            counter++;
        }

        return null;
        
    }
    //单链表转置
    public void reverse(){
        Node a=head;
        if(a==null){
            return ;
        }
        Node b=head.next;
        if(b==null){
            return ;
        }
        Node c=head.next.next;
        a.next=null;
        while(c!=null){
            b.next=a;
            a=b;
            b=c;
            c=c.next;
        }
        b.next=a;
        head=b;
    }
    //输出链表信息
    public void print(){
        Node current = head;  
        while(current!=null){
            System.out.println(current.value);
            current=current.next;
        }
        
    }
    
    public static void main(String[] args){
 
        ListNode l=new ListNode();
        l.addpre(3);
        l.addpre(2);
        l.addpre(1);
        l.add(7);
        l.add(8);
        l.add(9);
        l.delete(1);
        l.deletepos(4);
        l.reverse();
        l.print();
    }
    
}

class Node{
    public Node next;
    public int value;
    public Node(){
        next=null;
    }
    public Node(int v){
        value=v;
    }
}