List模拟栈

import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
public class Main<E>{    

    List<E> l = new LinkedList<>();//成员变量

    public void push(E i){
        l.add(i);
    }
    public E pop(){
        return ((LinkedList<E>) l).removeLast();
    }
    public boolean isempty(){
        if(l.isEmpty()==true){
            return true;
        }return false;
    }
    public int size(){
        return l.size();
    }
    public void clear(){
        l.clear();
    }
public static void main(String[] args) {
    Main<String> m = new Main<>();
    Scanner sc = new Scanner(System.in);
    for(int i=0;i<5;i++){
        m.push(sc.next());
    }

    m.clear();
    System.out.println(m.size());

}

}