[Java연습] 배열을 이용한 기본 스택 구현

/*
20240220 배열을 이용한 기본 스택 구현

*/
class MyStack{
    int[] arr;
    int top = -1;

    MyStack(int size){ //생성자
        arr = new int[size];
    }

    public boolean isEmpty(){
        if(this.top == -1){
            return true;
        }else {
            return false;
        }
    }

    public boolean isFull(){
        if(this.top == this.arr.length -1){
            return true;
        }else {
            return false;
        }
    }

    public void push(int data){
        if(this.isFull()){
            System.out.println("Stack is full!");
            return;
        }
        this.top += 1;
        this.arr[this.top] = data;
    }

    public Integer pop(){
        if(this.isEmpty()){
            System.out.println("Stack is empty!");
            return null;
        }
        int data = this.arr[this.top];
        this.top -= -1;
        return data;
    }

    public Integer peek(){
        if(this.isEmpty()){
            System.out.println("Stack is empty!");
            return null;
        }
        return this.arr[this.top];
    }

    public void printStack(){
        for (int i = 0; i < this.top +1 ; i++) {
            System.out.println(this.arr[i] + " ");
        }
        System.out.println();
    }

}

public class stackPractice01 {
    public static void main(String[] args){
        //test code 
        MyStack myStack = new MyStack(5);
        System.out.println(myStack.isEmpty());

        myStack.push(1);
        myStack.push(2);
        myStack.push(3);
        myStack.push(4);
        myStack.push(5);
        myStack.push(6);
        myStack.printStack();

        System.out.println(myStack.peek());
        myStack.printStack();

        System.out.println(myStack.pop());
        System.out.println(myStack.pop());
        myStack.printStack();

        System.out.println(myStack.pop());
        System.out.println(myStack.pop());
        System.out.println(myStack.pop());
        myStack.printStack();

    }
}