How to jump between flow in Java?

[Haswellx86]

Was writing a simple console game in Java. I am stuck in a situation where to continue further; I need to point the flow of the program to a while loop that comes earlier before this block of code I am talking about. The game is about creating a random integer, and I have to guess the integer and also get hints if I am close or far.

 

import java.util.Scanner;

public class GuessTheNumber{
    int input, random, lastInput;
    Scanner scanner = new Scanner(System.in);
    public void RandomValue(){
       random = (int) Math.random() * 100;
    }
    public void Input(){
        System.out.println("Guess The Number challenge!");
        System.out.println("Enter a number.");
        input = scanner.nextInt();
    }
    public void Compute(){
        if (random == input){
            System.out.println("You guessed the number on your first try!");
            System.out.println("The number is "+random);
            scanner.close();
        }
        else {
            if (Math.abs(random - input) >= 75){
                System.out.println("too high");
            }
            if (Math.abs(random - input) >= 50){
                System.out.println("high");
            }
            if (Math.abs(random - input) >= 25){
                System.out.println("low");
            }
            if (Math.abs(random - input) < 25){
                System.out.println("too low");
            }
            while(input != random){
                lastInput = input;
                input = scanner.nextInt();
                if (random == input){
                    System.out.println("You guessed the number!");
                    System.out.println("The number is "+random);
                    scanner.close();
                    break;
                }
                if (Math.abs(random - input) < Math.abs(random - lastInput)){
                    System.out.println("lower");
                }
                else {
                    System.out.println("Don't enter the same number!");
                    break;
                }
                if (Math.abs(random - input) > Math.abs(random - lastInput)){
                    System.out.println("higher");

                }
                else{
                    System.out.println("Don't enter the same number!");
                    break;
                }
            }
    }
}
    public static void main(String[] args){
        GuessTheNumber game = new GuessTheNumber();
        game.Input();
        game.RandomValue();
        game.Compute();
    }
    
}

 

First of all, this code already doesn't work as planned, but I will try to solve that later, but the main face problem is that at "Don't enter the same number", instead of the break, I need to jump the flow again to that while loop that is above it. How do I do it? "Goto" actually doesn't exist, I guess.

[YoungBlade]

Is there a reason you're using multiple if/else in a row? Why not just this, then you won't be using a break:

 

if (random == input){
    System.out.println("You guessed the number!");
    System.out.println("The number is "+random);
    scanner.close();
} else if (Math.abs(random - input) < Math.abs(random - lastInput)){
 	System.out.println("lower");
} else if (Math.abs(random - input) > Math.abs(random - lastInput)){
	System.out.println("higher");
} else {
	System.out.println("Don't enter the same number!");
}

 

[AbydosOne]

22 minutes ago, Hensen Juang said:

How do I do it? "Goto" actually doesn't exist, I guess.

The gist of it would be to run the entire program in a loop and only drop out of the loop once the conditions have been met.

 

int target = random();
ArrayList<Integer> previousGuesses = new ArrayList<>(10);

while (true) {
    int input = getInput();

    if (input == -1) {
        // quit
        break; // drops out of the loop
    }
    else if (previousGuesses.contains(input)) {
        // Choose another number
    }
    else if (input > target) {
        // too high
    }
    else if (input < target) {
        // too low
    }
    else {
        // you got it!
        break; // drops out of the loop
    }
    
    previousGuesses.add(input);
}

 

You also will need to keep track of your previous guesses, hence my ArrayList. You could also use a straight int[] and keep track of your index manually, but you have to be prepared to accept a large number of guesses, and ArrayList takes the work out of expanding the array.

 

P.S. Don't quote my Java verbatim, I'm running on memory.

 

P.P.S. Make sure you're following the Java standard naming capitalization rules (*hinthint* functions start lowercase).

[Biohazard777]

15 minutes ago, Hensen Juang said:

"Goto" actually doesn't exist, I guess.

There are labels, but you shouldn't be using them.

[Avocado Diaboli]

Ignoring the many redundant if-else statements, the basic problem with your while-loop is its position. Take that while-loop out of the else-statement of Compute. The logic of that if-else block is only about the very first guess, the while-loop is about all subsequent guesses. That means Compute should run through the if-else block once and then get stuck in the while loop until the correct number is guessed. Basically this:

 

if (input = random)
	// Hooray, you got it right on your first guess
} else {
	// Try again
}

while (input != random){
	// Do all the value checks and tell the player if they should guess higher or lower
}