如何用Java实现栈的功能 Java自定义栈结构实例展示

public class ArrayStack<T> {
    private T[] stack;
    private int top;
    private int capacity;

    public ArrayStack(int capacity) {
        this.capacity = capacity;
        this.stack = (T[]) new Object[capacity]; // 注意类型转换
        this.top = -1; // 初始化栈顶指针
    }

    public boolean isEmpty() {
        return top == -1;
    }

    public boolean isFull() {
        return top == capacity - 1;
    }

    public void push(T data) {
        if (isFull()) {
            throw new RuntimeException("Stack is full");
        }
        stack[++top] = data;
    }

    public T pop() {
        if (isEmpty()) {
            throw new RuntimeException("Stack is empty");
        }
        return stack[top--];
    }

    public T peek() {
        if (isEmpty()) {
            throw new RuntimeException("Stack is empty");
        }
        return stack[top];
    }

    public int size() {
        return top + 1;
    }

    public static void main(String[] args) {
        ArrayStack<Integer> stack = new ArrayStack<>(5);
        stack.push(1);
        stack.push(2);
        stack.push(3);

        System.out.println("Top element: " + stack.peek()); // Output: 3
        System.out.println("Popped element: " + stack.pop()); // Output: 3
        System.out.println("Current size: " + stack.size()); // Output: 2
    }
}

public class LinkedStack<T> {
    private static class Node<T> {
        T data;
        Node<T> next;

        Node(T data) {
            this.data = data;
        }
    }

    private Node<T> top;
    private int size;

    public LinkedStack() {
        this.top = null;
        this.size = 0;
    }

    public boolean isEmpty() {
        return top == null;
    }

    public void push(T data) {
        Node<T> newNode = new Node<>(data);
        newNode.next = top;
        top = newNode;
        size++;
    }

    public T pop() {
        if (isEmpty()) {
            throw new RuntimeException("Stack is empty");
        }
        T data = top.data;
        top = top.next;
        size--;
        return data;
    }

    public T peek() {
        if (isEmpty()) {
            throw new RuntimeException("Stack is empty");
        }
        return top.data;
    }

    public int size() {
        return size;
    }

    public static void main(String[] args) {
        LinkedStack<String> stack = new LinkedStack<>();
        stack.push("A");
        stack.push("B");
        stack.push("C");

        System.out.println("Top element: " + stack.peek()); // Output: C
        System.out.println("Popped element: " + stack.pop()); // Output: C
        System.out.println("Current size: " + stack.size()); // Output: 2
    }
}