GuessingGame.java

import java.util.Scanner;
import java.util.Arrays;

public class GuessingGame {

    private Scanner reader;

    public GuessingGame() {
        // use only this scanner, othervise the tests do not work
        this.reader = new Scanner(System.in);
    }

    public void play(int lowerLimit, int upperLimit) {
        this.instructions(lowerLimit, upperLimit);
//        int startingValue = average(upperLimit, lowerLimit);
        // int[] guesses = new int[howManyTimesHalvable(upperLimit - lowerLimit)];
//        guesses[0] = startingValue;
        // int average = 0;
        //int i = -1;
        while(true){
            int average = average(lowerLimit, upperLimit);
            if (isGreaterThan(average)) {
                lowerLimit = average + 1;
            } else {
                upperLimit = average;
            }
            if(lowerLimit == upperLimit) {
                System.out.println("The number you're thinking of is " + lowerLimit + ".");
                break;
            }
            
        }
        
        // System.out.println("The number you're thinking of is "+ lowerLimit);  
        
            
        //System.out.println("The number you're thinking about is " + lowerLimit + ".");

        // write the guessing logic here

    }

    // implement here the methods isGreaterThan and average

    public void instructions(int lowerLimit, int upperLimit) {
        int maxQuestions = howManyTimesHalvable(upperLimit - lowerLimit);

        System.out.println("Think of a number between " + lowerLimit + "..." + upperLimit + ".");

        System.out.println("I promise you that I can guess the number you are thinking with " + maxQuestions + " questions.");
        System.out.println("");
        System.out.println("Next I'll present you a series of questions. Answer them honestly.");
        System.out.println("");
    }

    // a helper method:
    public static int howManyTimesHalvable(int number) {
        // we create a base two logarithm  of the given value

        // Below we swap the base number to base two logarithms!
        return (int) (Math.log(number) / Math.log(2)) + 1;
    }
    
    public boolean isGreaterThan(int value) {
        String response = "";
        System.out.println("Is your number greater than " + value + "? (y/n)");
        response = reader.nextLine();
        return response.equals("y");
    }
    
    public int average(int firstNumber, int secondNumber) {
        return (firstNumber + secondNumber)/2;
    }
}