JAVA版本幼儿园减法计算训练

import java.util.Scanner;

public class SubtractionQuiz {
    public static void main(String[] args) {
        String need = "小学生练习减法运算";
        String step = "随机产生两个随机数，"
                + "进行显示这两个随机数，"
                + "计算两个数的差，"
                + "接收输入的计算结果，"
                + "进行检查给出计算是否正确";
        
        //create randomNumber System class 
        double number = System.currentTimeMillis();
        // 1.524465800663E12 
        System.out.println(number);
        
        double number1 = Math.random();
        //0.24660980596561355
        System.out.println(number1 );
        int n1 = (int)(Math.random() * 10);
        int n2 = (int)(Math.random() * 10);
        System.out.println(n1);
        System.out.println(n2);

        
        if(n1 < n2) {
            int temp = n1;
            n1 = n2;
            n2 = temp;
        }
        
        System.out.println("what is "+n1 + " - "+ n2+" ?");
        
        System.out.println("请输入计算结果：");
        
        int result = n1 -n2;
        //create Scanner a object
        Scanner input = new Scanner(System.in);
        
        int sub = input.nextInt();
        
        if(sub == result) {
            System.out.println("true");
        }else {                
            System.out.println("false");
        } 
    }
}