栈-后进先出

1、基本概念

? ? ? ? 栈只允许访问一个数据项：即最后插入的一个元素。只有移除最后一个元素之后，才能访问倒数第二插入的元素。

2、代码实现

public class Stack {
    public static void main(String[] args) {
        Stack stack = new Stack(10);
        //入栈
        for (int i = 0; i < 10; i++) {
            stack.push(i);
        }
        //出栈
        while (!stack.isEmpty()) {
            System.out.println(stack.pop());
        }
    }

    private long data[];
    private int top;
    private int capacity;

    public Stack(int capacity) {
        this.capacity = capacity;
        data = new long[capacity];
        top = -1;
    }
    //入栈
    public void push(long value) {
        if (top == capacity - 1) {
            System.out.println("Stack is full");
            return;
        }
        data[++top] = value;
    }
    //出栈
    public long pop() {
        return data[top--];
    }
    //查看栈顶元素
    public long peek() {
        return data[top];
    }

    //查看栈是否为空
    public boolean isEmpty() {
        return top == -1;
    }

    //判断栈是否满
    public boolean isFull() {
        return top == capacity - 1;
    }
}

3、经典实例

? ? ? ? 分隔符匹配