java初学者代码练习题

猜数字游戏，并显示答案边界值
import java.util.Random;
import java.util.Scanner;

public class GuessNumber {
    public static void main(String[] args) {
        Random ran=new Random();
        int num=ran.nextInt(100);
        //System.out.println(num);//作弊
        Scanner scan = new Scanner(System.in);
        System.out.println("猜数字游戏，请输入一个0~100的合法数字：");
        int big=100,small=0;
        while(true){
            System.out.println("输入一个数字");
            int guess=scan.nextInt();
            if(guess==-1){
                System.out.println("游戏结束")
                break;
            }else if(guess<0||guess>100){
                System.out.println("输入数字不合法，请重新输入：");
            }else if(guessnum){
                big=guess;
                System.out.println("猜错了，范围在"+small+"~"+big+"之间");
            }else{
                System.out.println("恭喜你答对了");
                break;
            }

        }
    }
}