53-java中的queue

import java.util.ArrayDeque;
import java.util.Queue;
import java.util.Scanner;
import java.util.Stack;

public class Main {
	public static int[][] mp = new int[55][55];
	public static char[] st = new char[1005];
	public static char[] end = new char[1005];
	
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        // 涉及到大量字符串拼接时不要用String， 而用StringBuilder
        StringBuilder st = new StringBuilder();
//        st.append(cin.next());
        
//        System.out.println(st);
        
        // java中的栈
        Stack<Integer> sta = new Stack<Integer>();
        // java中的队列：queue接口有很多实现类，建议查询jdk文档
        Queue<Integer> que = new ArrayDeque<>();
        
        que.add(1);
        que.add(2);
        que.add(9);
        que.add(2);
        
        System.out.println(que.toString());
        
        System.out.println(que.peek());
        System.out.println(que.toString());
        System.out.println(que.poll());
        System.out.println(que.toString());
        
    }
}
 
/*
abcd
dddd
3
a b
b c
c d
 */