[JAVA] STACK / QUEUE

import java.util.Scanner;

abstract class Memory {
    protected int[] m;
    protected int count;
    Memory(){ //생성자
        m = new int[20]; 
        count = 0; //초기화
    }

    public void push(int i) {
        if(full()) {
            m[count++] = i;
        }
    }
    
    //추상 클래스
    abstract int pop(); 
    abstract boolean full();
    abstract boolean empty();
}

class MyStack extends Memory{

    @Override
    public int pop() {
        if(empty()) {
            return m[--count];
        }
        else 
            return -1;
    }
    
    @Override
    public boolean full() {
        if(count == 20) {
            System.out.println("FULL");
            return false;
        }
        else
            return true;
    }
    
    @Override
    public boolean empty(){
        if(count == 0) {
            System.out.println("EMPTY");
            count = 0;
            return false;
        }
        else
            return true;
    }

}

class MyQueue extends Memory{
    private int front;
    
    public MyQueue() {
        front = 0;
    }
    
    @Override
    public int pop() {
        if(empty()) {
            return m[front];
        }
        else
            return -1;
    }
    
    @Override 
    public boolean full() {
        if(count == 20 && front == 0) {
            System.out.println("FULL");
            return false;
        }
        return true;
    }
    
    @Override
    public boolean empty() {
        if(count == front) {
            System.out.println("EMPTY");
            count = front = 0;
            return false;
        }
        else
            return true;
    }

}

public class SQ {
    public static void main(String[] args) {
        Memory m = null;
        MyStack ms = new MyStack();
        MyQueue mq = new MyQueue();
        Scanner s = new Scanner(System.in);
        int c = 0;
        while(c!=3) {
            System.out.println("1.Stack  2.Queue");
            System.out.print("선택 : ");
            c = s.nextInt();
            switch(c) {
            case 1 : //stack
                m = ms;
                System.out.println("1.Push  2.Pop");
                System.out.print("선택 : ");
                int sc = s.nextInt();
                if(sc == 1) {
                    System.out.print("입력 : ");
                    m.push(s.nextInt());
                }
                
                if(sc == 2) {
                    System.out.println(m.pop());
                }
                break;
            case 2 : //queue
                m = mq;
                System.out.println("1.Push  2.Pop");
                System.out.print("선택 : ");
                int qc = s.nextInt();
                if(qc == 1) {
                    System.out.print("입력 : ");
                    m.push(s.nextInt());
                }
                
                if(qc == 2) {
                    System.out.println(m.pop());
                }
                break;
            }
            
        }
        s.close();
    }
}