[자바] 배열로 스택 구현하기

배열로 스택 구현하기

package 패키지명;

import java.util.Scanner;

public class 클래스명 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt(); //최대값
		ArrayStack stack = new ArrayStack(n);
		while(true) {
			System.out.println(String.format("현재 수 : %d / %d", stack.size(), stack.capacity()));
			System.out.print("1.push, 2.pop, 3.peek, 4.clear, 5.dump, 0.종료 : ");
			int num = sc.nextInt();
			if(num == 0) break;
			
			int x;
			switch(num) {
			case 1:
				System.out.print("Push : ");
				x = sc.nextInt();
				stack.push(x);
				break;
			case 2:
				x = (int)stack.pop();
				System.out.println(String.format("Pop : %d", x));
				break;
			case 3:
				x = (int)stack.peek();
				System.out.println(String.format("Peek : %d", x));
				break;
			case 4:
				stack.clear();
				break;
			case 5:
				stack.dump();
				break;
			default:
				break;
			}
		}
	}
}

class ArrayStack{
	private int top;
	private int capacity;
	private Object stack[];
	public ArrayStack(int max) {
		this.top = -1;
		this.capacity = max;
		stack = new Object[max];
	}
	
	public void push(Object obj) { //넘치면(full) 에러만 표시
		if(isFull()) {
			System.out.println("Stack is Full!!");
		}else {
			stack[++top] = obj;
		}
	}
	
	public Object peek() {
		return stack[top];
	}
	
	public Object pop() {
		if(isEmpty()) {
			System.out.println("Stack is Empty!!!");
			return null;
		}else {
			Object obj = stack[top];
			stack[top] = null;
			--top;
			
			return obj;
		}
		
	}
	
	public void clear() {
		this.top = -1;
		stack = new Object[this.capacity];
	}
	
	public boolean isEmpty(){		
		return (this.top == -1);
	}
	
	public boolean isFull() {
		return (this.top >= this.capacity - 1);
	}
	
	public int size() {
		return this.top + 1;
	}
	
	public int capacity() {
		return this.capacity;
	}
	
	public void dump() {
		for(Object obj : stack) {
			if(obj != null) {
				System.out.print(String.format("%s ", obj.toString()));
			}
		}
		System.out.println();
	}
}