[DAY 07] Stack and Queue (Version 1.1)

Main.java

package day_07_homework;
 
import java.util.Scanner;
 
public class Main {
 
    public static void main(String[] args) {
 
        Scanner sc = new Scanner(System.in);
 
        Memory me = null;
        MyStack ms = new MyStack();
        MyQueue mq = new MyQueue();
 
        int data;
 
        do {        
            System.out.println("\n" + "========================");
            System.out.println("수행할 자료구조를 선택하세요.");
            System.out.println("1. Stack data structure");
            System.out.println("2. Queue data structure");
            System.out.println("3. Exit");
            System.out.println("========================");
 
            int selDS = sc.nextInt();
 
            if(selDS == 1) {            // dynamic binding to stack
                me = ms;
            } else if(selDS == 2) {        // dynamic binding to queue
                me = mq;
            } else if(selDS == 3) {        // exit
                System.out.println("프로그램을 종료합니다.");
                System.exit(0);
            } else {
                System.out.println("잘못된 번호를 입력하였습니다. 다시 입력하세요.");
                continue;
            }
 
            while(true) {
                System.out.println("\n" + "========================");
                System.out.println("수행할 연산을 선택하세요.");
                System.out.println("1. Push operation");
                System.out.println("2. Pop operation");
                System.out.println("3. Exit");
                System.out.println("========================");
 
                int num = sc.nextInt();
                if(num == 1) {
                    if(!me.checkOverflow()) {
                        System.out.println("\n" + "========================");
                        System.out.println("Input data : ");
                        me.push(sc.nextInt());
                        System.out.println("Complete!");
                        System.out.println("========================");
                    }
                } else if(num == 2) {
                    if(!me.checkUnderflow()) {
                        data = me.pop();
                        System.out.println("\n" + "========================");
                        System.out.println("Print out data : " + data);
                        System.out.println("========================");
                        if(me instanceof MyQueue) {
                            mq.shiftData();
                        }
                    }
                } else if(num == 3) {
                    break;
                } else {
                    System.out.println("잘못된 번호를 입력하였습니다. 다시 입력하세요.");
                    continue;
                }
            }
 
        } while(true);
 
    }    // main period
 
}    // class period

Memory.java

package day_07_homework;
 
public abstract class Memory {
 
    // field
    protected int pos;
    protected int []data;
 
    // constructor
    public Memory() {
        data = new int[5];
        pos = 0;
    }
    
    public boolean checkOverflow() {
        if(pos > 4) {
            System.out.println("Overflow!");
            return true;
        }
        return false;
    }
 
    public boolean checkUnderflow() {
        if(pos < 1) {
            System.out.println("Underflow!");
            return true;
        }
        return false;
    }
 
    public void push(int num) {
        data[pos++] = num;
    }
    
    // abstract method
    public abstract int pop();
    
}

MyStack.java

package day_07_homework;
 
public class MyStack extends Memory {
 
    public int pop() {
        return data[--pos];
    }
    
}

MyQueue.java

package day_07_homework;
 
public class MyQueue extends Memory {
 
    private int front;
    
    public MyQueue() {
        front = 0;
    }
        
    public int pop() {
        return data[front++];
    }
    
    public void shiftData() {
        for(int i = 0; i<pos-1; i++) {
            data[i] = data[i+1];
        }
        pos--;
        front--;
    }
 
}