数组模拟栈

public class MyStack {

private int top;

    private int[] arr;

    public MyStack(int size) {

arr = new int[size];

}

public boolean isEmpty() {

return top == 0;

}

public boolean isFull() {

return top == arr.length;

}

public void push(int data) {

if(isFull()){

throw new RuntimeException("数据满了");

}

arr[top++] = data;

}

public int pop() {

if(isEmpty()){

System.out.println("空了");

          throw new RuntimeException("没数据了");

}

return arr[--top];

}

public int size() {

return top;

}

public static void main(String[]args){

MyStack myStack = new MyStack(6);

myStack.push(1);

myStack.push(2);

myStack.push(3);

myStack.push(4);

myStack.push(5);

myStack.push(6);

System.out.println("pop:"+myStack.pop());

System.out.println("size:"+myStack.size());

//    System.out.println("pop:"+myStack.pop());

//    System.out.println("pop:"+myStack.pop());

//    System.out.println("pop:"+myStack.pop());

//    System.out.println("pop:"+myStack.pop());

}

}