我想写一个程序，允许用户在7次尝试中猜测一个0到100之间的数字。我不知道为什么这不起作用

Question

public class Main {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int rnd = (int)(Math.random() * 101);

        System.out.println("The program is going to give a number that is between 0 and 100 (including them). You can guess it by pressing Run.");
        System.out.println("Enter your number:");
        int num = scan.nextInt();

        for (int count = 1; count <= 7; count++) {
            while (num != rnd) {
                if (num < rnd) {
                    System.out.println("Your guess is too low.");
                }
                if (num > rnd) {
                    System.out.println("Your guess is too high.");
                }
                if ((Math.abs(rnd - num) == 1) || (Math.abs(rnd - num) == 2)) {
                    System.out.println("But your guess is VERY close.");
                }
                num = scan.nextInt();
            }
            System.out.println("You got it right!");
        }
        System.out.println("You should guess it in 7 tries.");
    }
}

所以我用了两个循环，只是嵌套它们。这就是它的工作原理吗？现在，代码就像是从for循环开始，如果这是真的，它就会转到while循环部分，在那里猜测数字。仅仅通过移动一些代码和修复周围的小区域就可以解决这个问题吗？

Answer 1

public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    final int rnd = new Random().nextInt(101);
    final int maxAttempts = 7;

    System.out.println("The program is going to give a number that is between 0 and 100 (including them).");
    System.out.println("You can guess it within maximum " + maxAttempts + " attempts by pressing Run.");
    boolean success = false;

    for (int attempt = 1; attempt <= maxAttempts && !success; attempt++) {
        System.out.format("(%s of %s) Enter your number: ", attempt, maxAttempts);
        int num = scan.nextInt();

        if (num == rnd)
            success = true;
        else {
            System.out.print("Your guess is too " + (num > rnd ? "high" : "low") + '.');
            System.out.println(Math.abs(rnd - num) <= 2 ? " But it's VERY close." : "");
        }
    }

    System.out.println(success ? "You got it right!" : "Bad luck this time. Buy.");
}

Answer 2

import java.util.Scanner;

class Main {
  public static void main(String[] args) 
  {
    Scanner scan = new Scanner(System.in);
    int rnd = (int) (Math.random() * 101);

    System.out.println("The program is going to give a number that is between 0 and 100 (including them). You can guess it by pressing Run.");
    System.out.println("Enter your number:");
    int num = scan.nextInt();
    
    for(int count = 1; count <= 7; count++)
    {
        if (num < rnd)
        {
          System.out.println("Your guess is too low.");
        }
        else if (num > rnd)
        {
          System.out.println("Your guess is too high.");
        }
        else if ((Math.abs(rnd - num) == 1) || (Math.abs(rnd - num) == 2))
        {
          System.out.println("But your guess is VERY close.");
        }
        else
          System.out.println("You got it right!");

        System.out.println("Enter Next number: ");
        num = scan.nextInt();
    }
}

应该能正常工作。

Answer 3

在这种情况下，您应该手动执行代码。字面意思。拿张纸假装你是一台电脑。这是一个很好的练习，它会帮助你解决你的问题。

问题是你的内循环。它循环直到他们猜对为止，而不考虑尝试的次数。然后你强迫他们用外圈再做6次。

你真的只需要1个循环。我会有一个这样的循环:

int attempts = 0;
int num = 0;
do {
    num = scan.nextInt();
    ... most of the if code from your inner loop but not another scan.nextInt
} while (++attempts < 7 && num != rnd);
// and here you look at num == rnd to see if success or failures