Java集合篇之逐渐被遗忘的Stack，手写一个栈你会吗？

 * The root interface in the <i>collection hierarchy</i>.  A collection
 * represents a group of objects, known as its <i>elements</i>.  Some
 * collections allow duplicate elements and others do not.  Some are ordered
 * and others unordered.  The JDK does not provide any <i>direct</i>
 * implementations of this interface: it provides implementations of more
 * specific subinterfaces like <tt>Set</tt> and <tt>List</tt>.  This interface
 * is typically used to pass collections around and manipulate them where
 * maximum generality is desired.

* This class consists exclusively of static methods that operate on or return
* collections.  It contains polymorphic algorithms that operate on
* collections, "wrappers", which return a new collection backed by a
* specified collection, and a few other odds and ends.

Stack<String> stacks = new Stack<>();
//push方法入栈
 stacks.push("开");
 stacks.push("工");
 stacks.push("大");
 stacks.push("吉");
 stacks.push("！");
 System.out.println(stacks);
 //pop栈顶元素出栈
 String pop = stacks.pop();
 System.out.println(pop);
 //查看栈顶元素
 String peek = stacks.peek();
 System.out.println(peek);
 //判断堆栈是否为空
 boolean empty = stacks.empty();
 System.out.println(empty);
 //查看元素在堆栈中的位置
 int index = stacks.search("开");
 System.out.println(index);

[开, 工, 大, 吉, ！]
！
吉
false
4

/**
 * @ClassName Stack
 * @Description 手写一个int类型的堆栈
 * @Author hzm
 * @Date 2024/2/18 14:21
 * @Version 1.0
 */
public class Stack {
    private int arr[];
    private int top;
    private int capacity;

    /**
     * 提供一个有参构造，初始化栈
     * @param size
     */
    public Stack(int size) {
        this.arr = new int[size];
        this.top = -1;
        this.capacity = size;
    }

    /**
     * 入栈
     * @param p
     */
    public void push(int p) {
        if (isFull()) {
            System.out.println("堆栈空间溢出\n程序终止\n");
            System.exit(1);
        }

        System.out.println("入栈:" + p);
        arr[++top] = p;
    }

    /**
     * 出栈
     * @return
     */
    public int pop() {
        if (isEmpty()) {
            System.out.println("空栈，不可POP");
            System.exit(1);
        }
        return arr[top--];
    }

    /**
     * 判断栈是否已满
     * @return
     */
    public Boolean isFull() {
        return top == capacity - 1;
    }

    /**
     * 判断栈是否为空
     * @return
     */
    public Boolean isEmpty() {
        return top == -1;
    }

    /**
     * 遍历栈内元素
     */
    public void printStack() {
        for (int i = 0; i <= top; i++) {
            System.out.println(arr[i]);
        }
    }

    /**
     * 返回栈的大小
     * @return
     */
    public int size() {
        return top + 1;
    }

    /**
     * 查看栈顶元素
     * @return
     */
    public void peek(){
        System.out.println("栈顶元素：" + arr[top]);
    }
}

public class Test {
    public static void main(String[] args) {
        Stack stack = new Stack(5);
        //入栈
        stack.push(1);
        stack.push(2);
        stack.push(3);
        stack.push(4);
        stack.push(5);
        //出栈
        int pop = stack.pop();
        System.out.println("出栈："+ pop);
        //查看栈的大小
        int size = stack.size();
        System.out.println("栈容量：" + size);
        //查看栈顶元素
        stack.peek();
        //打印栈内元素
        stack.printStack();
    }
}

入栈:1
入栈:2
入栈:3
入栈:4
入栈:5
出栈：5
栈容量：4
栈顶元素：4
1
2
3
4