【数据结构与算法 | 基础篇】数组模拟栈

1. 前言

前文我们刚提及了如何用单向链表来模拟栈. 我们还可以用数组来模拟栈.使用栈顶指针top来进行栈顶的操作.

2. 数组模拟栈

(1). 栈接口

public interface stack<E> {//压栈boolean push(E value);//弹栈, 栈非空返回栈顶元素E pop();//返回栈顶元素, 但不弹栈E peek();//判断栈是否为空boolean isEmpty();//判断栈是否已满boolean isFull();
}

(2). 数组模拟栈

public class ArrayStack<E> implements stack<E>, Iterable<E>{//栈顶指针private int top;//数组模拟栈private E[] stack;public ArrayStack(int capacity) {stack = (E[]) new Object[capacity];}@Overridepublic boolean push(E value) {if(isFull()) {return false;}stack[top++] = value;return true;}@Overridepublic E pop() {if(isEmpty()) {return null;}return stack[--top];}@Overridepublic E peek() {if (isEmpty()) {return null;}return stack[top-1];}@Overridepublic boolean isEmpty() {return top < 0;}@Overridepublic boolean isFull() {return top == stack.length;}@Overridepublic Iterator<E> iterator() {return new Iterator<E>() {@Overridepublic boolean hasNext() {return top > 0;}@Overridepublic E next() {return stack[--top];}};}
}

3. 单元测试

public class ArrayStackTest {@Testpublic void test1() {ArrayStack<Integer> stack = new ArrayStack<>(10);stack.push(1);stack.push(2);stack.push(3);stack.push(4);stack.push(5);stack.push(6);stack.push(7);for (Integer element : stack) {System.out.print(element + " ");}//7 6 5 4 3 2 1}@Testpublic void test2() {ArrayStack<Integer> stack = new ArrayStack<>(10);stack.push(1);stack.push(2);stack.push(3);stack.push(4);stack.push(5);stack.push(6);stack.push(7);System.out.println(stack.peek());//7System.out.println(stack.pop());//7System.out.println(stack.peek());//6}
}