1、栈

package test;

public class Stack {
    private int array[];
    private int max;
    private int top;

    public Stack(int max){
        this.max=max;
        array=new int[max];
        top = 0;
    }

    public void push(int value){
        if(isFull()){
            System.out.println("full, can not insert");
            return;
        }
        array[top++]=value;
    }

    public int pop(){
        return array[--top];
    }

    private boolean isEmpty(){
        if(top == 0){
            return true;
        }
        return false;
    }

    private boolean isFull() {
        // TODO Auto-generated method stub
        if(top == max){
            return true;
        }
        return false;
    }

    public void display(){
        while(!isEmpty()){
            System.out.println(pop());
        }
    }

    public static void main(String[] args) {
        Stack s = new Stack(5);
        s.push(1);
        s.push(3);
        s.push(5);
        s.push(7);
        s.push(9);
        s.display();
    }

运行结果

2、OJ题：单词逆序（错误）

package test;

import java.util.Scanner;

public class Stack {
    private int array[];
    private int max;
    private int top;

    public Stack(int max){
        this.max=max;
        array=new int[max];
        top = 0;
    }

    public void push(int value){
        if(isFull()){
            System.out.println("full, can not insert");
            return;
        }
        array[top++]=value;
    }

    public int pop(){
        return array[--top];
    }

    private boolean isEmpty(){
        if(top == 0){
            return true;
        }
        return false;
    }

    private boolean isFull() {
        // TODO Auto-generated method stub
        if(top == max){
            return true;
        }
        return false;
    }

    public void display(){
        while(!isEmpty()){
            System.out.println(pop());
        }
    }

    public String reverse(String in){
        String out = "";
        for (int i = 0; i < in.length(); i++) {
            char c = in.charAt(i);
            push(c);
        }
        while(!isEmpty()){
            out += pop();
        }
        return out;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.nextLine();
        Stack s = new Stack(str.length());
        System.out.println(s.reverse(str));
    }


}