Guessing Game program. User thinks of number, computer tries to guess it

Question

import java.util.Scanner;
import java.util.Random;

public class GuessHarder {

public static void main(String[] args) {


    Random generator = new Random();
    Scanner reader = new Scanner(System.in);

    String higher = "higher", lower = "lower", correct = "correct", input;
    int guess, random, random2 = 1, random3 = 100, randomLast, cntr = 1;

    random = generator.nextInt(100) + 1;
    randomLast = random;
    System.out.println("Is your number: " + random);
    System.out.println("Input if number should be higher, lower, or correct: ");
    input = reader.next();

    while (!input.equals("correct")){
        if (input.equals("lower")){
            randomLast = random2;
            random2 = generator.nextInt(100) + 1;
            if ((random2 < random) && (random2 < randomLast)){
            random = random2;
            cntr += 1;
            System.out.println("Is your number: " + random);
            System.out.println("Input if number should be higher, lower, or correct: ");
            input = reader.next();
            } else {
                input = lower;
            }
        } else if (input.equals("higher")){
            randomLast = random3;
            random3 = generator.nextInt(100) + 1;
            if ((random3 > random) && (random3 > randomLast)){
            random = random3;
            cntr += 1;
            System.out.println("Is your number: " + random);
            System.out.println("Input if number should be higher, lower, or correct: ");
            input = reader.next();
            } else {
                input = higher;
            }
        }

    }

    System.out.println("Computer took " + cntr + " amount of tries to guess your number");

    }
}

When I input higher or lower it will give me the number higher or lower than the previous respectively but it won't remember previous numbers. For clarity an example would be:

"Is your number: 65

Input if number should be higher, lower, or correct:

higher

Is your number: 96

Input if number should be higher, lower, or correct:

lower

Is your number: 59

Input if number should be higher, lower, or correct:"

The range by the last input should have been 65-96, but instead it just does 0-96 so I get numbers like 59 that shouldn't be in the range. What should I change to set it up to remember last two inputs for range instead of just the last.

Answer 1

So keep two variables that "remember" the lower and upper bounds.

int lowerBound = 0;
int upperBound = MAX_NUMBER;

Then each time the computer makes a guess you need to update these two numbers.

Once you update the two numbers you need to generate a new guess based on those numbers.

generator.nextInt(upperBound - lowerBound + 1) + lowerBound;

The +1 makes the value inclusive.

Answer 2

You have to remember the lower and the upper bound and try to make a random number between them instead of

generator.nextInt(100) + 1;