Java中的二进制猜谜游戏

Question

I am trying to create a guessing game that takes an input from a user. My issue is, when the user guesses incorrectly, the right digit of he binary number must be revealed, and so on.

However, I am having issues with the order and length of the output.

What I need:

RANDOM VALUE GENERATED: 11

Binary number to guess: 1011

Display shown to user: ----

Display shown after first incorrect guess: ---1

Display shown after second incorrect guess: --11

Display shown after third incorrect guess: -011

Display shown after fourth incorrect guess: 1011

What I get:

RANDOM VALUE GENERATED: 11

Binary number to guess: 1011

Display shown to user: -------

Display shown after first incorrect guess: ------0

Display shown after second incorrect guess: -----00

Display shown after third incorrect guess: ----000

Display shown after fourth incorrect guess: ---0000

Display shown after fifth incorrect guess: --10000

Display shown after sixth incorrect guess: -010000

Display shown after seventh incorrect guess: 1010000

My code:

Scanner scan = new Scanner(System.in);

        // Generating a random number between 1-16
        int randomNum = (int) (Math.random() * 16 + 1);
        int original = randomNum;
        System.out.println("Random num generated: " + randomNum);

        // Converting the random number to a binary number
        System.out.print("Random number in binary: ");
        int[] binary = new int[8];
        int originalBinary = 0;
        int index = 0;
        int count = 0;

        while (randomNum > 0) {
            binary[index++] = randomNum % 2;
            randomNum /= 2;
        }
        for (int i = index - 1; i >= 0; i--) {
            count++;

            System.out.print(binary[i]);
            originalBinary = binary[i];
        }
        System.out.println("\n***********************************");

        // System.out.print("\nPlease enter a guess: ");
        int guess = scan.nextInt();
        int digitsToReveal = 0;

        while (guess != original && digitsToReveal != binary.length) {

            System.out.print("\nPlease enter another number: ");
            guess = scan.nextInt();
            System.out.println(reveal(binary, digitsToReveal++));

        }

    }

    public static String reveal(int[] arr, int reveal) {
        StringBuilder str = new StringBuilder();
        for (int i = 1; i < arr.length; i++) {
            if (i >= arr.length - reveal) {
                str.append(arr[i]);
            } else {
                str.append("-");
            }

        }
        return str.toString();
    }
}

Answer 1

Note that your binary array stores the bits of the integer in the reverse order in which you printed it. That is, binary[0] is the most significant bit. For example, for the number 13 (binary 1101), the array looks like:

[1, 0, 1, 1, 0, 0, 0, 0]

When printing the binary version of the integer, you correctly read the array in reverse:

for (int i = index - 1; i >= 0; i--) {
    System.out.print(binary[i]);
}

So in reveal , you should read the array in reverse too:

public static String reveal(int[] arr, int reveal) {
    StringBuilder str = new StringBuilder();
    for (int i = 1; i < arr.length; i++) {
        if (i >= arr.length - reveal) {
            // note the change here:
            str.append(arr[arr.length - i - 1]);
        } else {
            str.append("-");
        }

    }
    return str.toString();
}

Rather than i , you should access arr.length - i - 1 .

Also, note that an array of length 5 can sufficiently store numbers from 1 to 16, you don't need to use an array of length 8.

---

I don't know if this is intentional or not, but you are not revealing the most significant bit.

Answer 2

Because of you are store binary number in the revers order to binary array variable

Number : 11

Binary : 1011

array : [1, 1, 0, 1, 0, 0, 0, 0]

I fix this by store it at last to first element of an binary array by starting index variable with 7 and index-- in while loop. And I edit digitToReveals = 1 and move reveal calling method to first line in while loop, this will reveal the number since first wrong guessing.

import java.util.Scanner; // Import the Scanner class

public class GuessFromBinary {

  public static void main(String[] args) {

    Scanner scan = new Scanner(System. in );

    // Generating a random number between 1-16
    int randomNum = (int)(Math.random() * 16 + 1);
    int original = randomNum;
    System.out.println("Random num generated: " + randomNum);

    // Converting the random number to a binary number
    System.out.print("Random number in binary: ");
    int[] binary = new int[8];
    int index = 7;

    while (randomNum > 0) {
      binary[index--] = randomNum % 2;
      randomNum /= 2;
    }

    for (int i = index + 1; i < 8; i++) {
      System.out.print(binary[i]);
    }

    System.out.println("\n***********************************");

    System.out.print("\nPlease enter a guess: ");
    int guess = scan.nextInt();

    int digitsToReveal = 1;

    while (guess != original && digitsToReveal != binary.length) {
      System.out.println(reveal(binary, digitsToReveal++));
      System.out.print("\nPlease enter another number: ");
      guess = scan.nextInt();
    }

    if (guess == original) System.out.print("\nYes!");
    else System.out.print("\nNo luck :(");

  }

  public static String reveal(int[] arr, int reveal) {
    StringBuilder str = new StringBuilder();
    for (int i = 1; i < arr.length; i++) {
      if (i >= arr.length - reveal) {
        str.append(arr[i]);
      } else {
        str.append("-");
      }

    }
    return str.toString();
  }
}

And I also adjust some other things (unused variable, message interactions, ...). You give a player 8 times to guess per round if I didn't misunderstand.