随机数博弈问题（用户挑数，计算机猜）

Question

在这个程序中，用户必须想出一个数字，然后让计算机来猜。

2.我试过这个程序，但电脑的猜测很奇怪。计算机不会根据我的指南猜出一个数字。

public class Guess
{

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        Random rand = new Random();

        //ask about the lower bound,
        TextIO.putln("Hey there! Welcom to the game!\n"
                + "I'm going to guess a number, and you have to pick it\n"
                + "and you get to decide the bounds.\n" +
                "What should the lower bound be?");
        int lowerlimit = TextIO.getInt();

        //if the user enter the number lower than 0,
        while ((lowerlimit < 0))
        {
            TextIO.putln("ERROR Please enter a number that greater than 0");
            lowerlimit = TextIO.getInt();
        }

        //ask about the upper bound,
        TextIO.putln("Great! How about the upper bound?");
        int upperlimit = TextIO.getInt();

        //if the user enter the number lower than 0,
        while ((upperlimit <= lowerlimit))
        {
            TextIO.putln("ERROR Please enter a number "
                    + "that greater than the lower bound.");
            upperlimit = TextIO.getInt();
        }

        //Print the range and instruction,  
        TextIO.putln("Ok. In the range between " + lowerlimit +
                " and " + upperlimit + ":" + "\nPlease enter 'lower'/'higher' "
                + "when the number I picked is not correct\n"
                + "Enter 'yes' when I picked the right number"
        );

        //Generate the random number between the range,
        int randNum = (int) ((Math.random() * ((upperlimit - lowerlimit) + 1)) + lowerlimit);
        String feedback = "";


        while (!feedback.equals("yes"))
        {
            TextIO.putln("I think it is " + randNum);
            feedback = in.nextLine();

            //When the computer need to pick a lower number, 
            if (feedback.equals("lower"))
            {
                upperlimit = randNum - 1;
                randNum = (int) ((Math.random() * ((upperlimit - lowerlimit) + 1)) + lowerlimit);

            }

            //When the computer need to pick a higher number, 
            else if (feedback.equals("higher"))
            {
                lowerlimit = randNum + 1;
                randNum = (int) ((Math.random() * ((upperlimit - lowerlimit) + 1)) + lowerlimit);

            }
        }
        {
            //When the user guesses the correct number,
            TextIO.putln("Yes! Correct!:)");
        }
        in.close();
    }

    public static int randomInt(int min, int max) {
        return (int) ((Math.random() * ((max - min) + 1)) + min);
    }
} // end of Guess class

Answer 1

我看了你的代码，我改变了一点。我认为我的变化将反映出你可以做些什么来变得更好，但有些注释：

1. 必须使用securerandom类，这样要好得多。您必须使用NextInt来获取随机数，我只创建一个该类型的对象
2. 您可以在while中计算随机数1，直到得到真正的结果。
3. 必须在.next()中使用，因为在读取字符串之前会忽略空间。如果使用nextline()，则nextint()只读取number，而nextline()将首先捕获零字符串。

它是改进的代码：

public class Guess
{
    public static SecureRandom random = new SecureRandom();
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);

        //ask about the lower bound
        System.out.println("Hey there! Welcome to the game!\n"
                + "I'm going to guess a number, and you have to pick it\n"
                + "and you get to decide the bounds.\n" +
                "What should the lower bound be?");
        int lower = in.nextInt();

        //if the user enter the number lower than 0
        while (lower < 0)
        {
            System.out.println("ERROR Please enter a number that greater than 0");
            lower = in.nextInt();
        }

        //ask about the upper bound
        System.out.println("Great! How about the upper bound?");
        int upper = in.nextInt();

        //if the user enter the number lower than 0
        while (upper <= lower)
        {
            System.out.println("ERROR Please enter a number "
                    + "that greater than the lower bound.");
            upper = in.nextInt();
        }

        //Print the range and instruction
        System.out.println("Ok. In the range between " + lower +
                " and " + upper + ":" + "\nPlease enter 'lower'/'higher' "
                + "when the number I picked is not correct\n"
                + "Enter 'yes' when I picked the right number"
        );

        //Generate the random number between the range
        String feedback = "";

        while (!feedback.equals("yes"))
        {
            int randNum = lower + random.nextInt(upper - lower + 1);
            System.out.println("I think it is " + randNum);
            feedback = in.next();

            //When the computer need to pick a lower number,
            if (feedback.equals("lower"))
                upper = randNum - 1;

            // When the computer need to pick a higher number,
            if (feedback.equals("upper"))
                lower = randNum + 1;
        }
        //When the user guesses the correct number,
        System.out.println("Yes! Correct!");
        in.close();
    }
}

我希望这能帮到你。