Java学习记录（随机数猜测）

代码如下：

package cn.itcast.demo1;

import java.util.Random;
import java.util.Scanner;

public class random {
    public static void main(String[] args) {
        Random random = new Random();
        int c = random.nextInt(20);
        int r = c+500;
        System.out.println(r);
        Scanner sc = new Scanner(System.in);
        while (true) {
            int a = sc.nextInt();
            if (a>r)
                System.out.println("选则数过大");
            if (a