[Java] 큐(Queue) 코드 구현

선입선출(FIFO, First in first out) 방식의 자료구조.

 

package QueueList;

import java.util.ArrayList;
import java.util.Scanner;

public class Queuetest {
	Scanner sc = new Scanner(System.in);
	ArrayList<String> al;
	
	public 	Queuetest(){
		al = new ArrayList<String>();
	}
	public int push(){
		System.out.print(" 입력 : ");
		al.add(sc.next());
		return 1;
	}
	public int pop(){
		al.remove(0);
		return 1;
	}
	public int getFirst(){
		System.out.println(al.get(0));
		return 1;
	}
	public int listSize(){
		for(int i = 0; i < al.size(); i++){
			System.out.print(al.get(i));
		}
		return 1;
	}

}

 

실행

package QueueList;

public class mainClass {

	public static void main(String[] args) {
		Queuetest cls = new Queuetest();
		
		cls.push();
		cls.push();
		cls.push();
		cls.listSize();
		cls.getFirst();
		cls.pop();
		cls.listSize();
	}
}