just a tiny program from a newcomer to java to test a bit your brain power in basic mathematics operations

Train Your Brain

/*
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 * and open the template in the editor.
 */
package trainyourbrain;

import java.util.*;

/**
 *
 * @author Lalabol
 */
public class TrainYourBrain {

    /**
     * @param args the command line arguments
     */
    
    String userChoice;
    double argumentMaxNumber;
    int maxNumber;
    int question1;
    int question2;
    int question3;
    boolean userWant;
    int rightAnswers;
    int numberOfTries;
    int numberOfSkips;
    
    public static void main(String[] args) {
        System.out.println("Hello and welome to Train Your Brain!");
        System.out.println("Press 1-5 to choose desired algebraic operator:");
        System.out.println("1.Addition");
        System.out.println("2.Subtraction");
        System.out.println("3.Multiplication");
        System.out.println("4.Division");
        System.out.println("5.Exponential");
        TrainYourBrain game = new TrainYourBrain();
        game.availableOperators();
    }//end of a main method
    
    
    public String getUserChoice(){
        String[] arrayOfOperators = {"Addition", "Subtraction", "Multiplication", "Division", "Exponential"};
        int numberOperator;
        Scanner inputUserChoice = new Scanner (System.in);
        System.out.println("Please enter valid number from 1 to 5");
        String userChoice = inputUserChoice.next();
        try{
            numberOperator = Integer.parseInt(userChoice);
            System.out.println("You have chose " + userChoice + "." + arrayOfOperators[numberOperator - 1]);
            return userChoice;
        }catch (java.lang.ArrayIndexOutOfBoundsException outOfRange){
            getUserChoice();
        }catch (java.lang.NumberFormatException numberFormat){
            getUserChoice();
        }
        return userChoice;
    }//end of a method getUserChoice()
        
    public int getUserMaxNumber(){
        try{
            Scanner inputMaxNumber = new Scanner(System.in);
            System.out.println("Enter maximum available number:");
            int maxNumber = inputMaxNumber.nextInt();
            System.out.println("You have entered " + maxNumber);
            return maxNumber;
        }catch (java.util.InputMismatchException notANumber){
            System.out.println("You have entered not a valid number");
            getUserMaxNumber();
        }
        return maxNumber;
    }//end of a method getUserMaxNumber()
    
    public void availableOperators(){
        String c = getUserChoice();
        switch (c){
            case "1":
                argumentMaxNumber = getUserMaxNumber();
                operatorAddition(argumentMaxNumber);
                break;
            case "2":
                argumentMaxNumber = getUserMaxNumber();
                operatorSubtraction(argumentMaxNumber);
                break;
            case "3":
                argumentMaxNumber = getUserMaxNumber();
                operatorMultiplication(argumentMaxNumber);
                break;
            case "4":
                argumentMaxNumber = getUserMaxNumber();
                operatorDivision(argumentMaxNumber);
                break;
            case "5":
                argumentMaxNumber = getUserMaxNumber();
                operatorPow(argumentMaxNumber);
                break;
            default:
                System.out.println("Choose the right option:");
                availableOperators();
        }
    }//end of a method availableOperators()
    
    public void operatorAddition(double o){
        do{
            question1 = (int)(Math.random() * argumentMaxNumber);
            question2 = (int)(Math.random() * argumentMaxNumber);
            question3 = question1 + question2;
            System.out.println("How much is " + question1 + " + " + question2 + " ?");
            System.out.println("Enter 0 to skip this question");
            evaluateUserAnswer();
        } while(userWantToPlay());
        finishGame();
    }//end of a method operatorAddition()
    
    public void operatorSubtraction(double o){
        do{
            question1 = (int)(Math.random() * argumentMaxNumber);
            question2 = (int)(Math.random() * argumentMaxNumber);
            question3 = question1 - question2;
            System.out.println("How much is " + question1 + " - " + question2 + " ?");
            System.out.println("Enter 0 to skip this question");
            evaluateUserAnswer();
        } while(userWantToPlay());
        finishGame();
    }//end of a method operatorSubtraction()
    
    public void operatorMultiplication(double o){
        do{
            question1 = (int)(Math.random() * argumentMaxNumber);
            question2 = (int)(Math.random() * argumentMaxNumber);
            question3 = question1 * question2;
            System.out.println("How much is " + question1 + " x " + question2 + " ?");
            System.out.println("Enter 0 to skip this question");
            evaluateUserAnswer();
        } while(userWantToPlay());
        finishGame();
    }//end of a method operatorMultiplication()
    
    public void operatorDivision(double o){
        do{
            question1 = (int)(Math.random() * argumentMaxNumber);
            question2 = (int)(Math.random() * argumentMaxNumber);
            try{
                question3 = Math.max(question1, question2) / Math.min(question1, question2);
                System.out.println("What is the algebraic quotient of division of " + Math.max(question1, question2) + " by " + Math.min(question1, question2) + " ?");
            } catch(java.lang.ArithmeticException divisionByZero){
                continue;
            }
            System.out.println("Enter 0 to skip this question");
            evaluateUserAnswer();
            } while(userWantToPlay());
            finishGame();
    }//end of a method operatorDivision()
    
    public void operatorPow(double o){
        do{
            question1 = (int)(Math.random() * argumentMaxNumber);
            question2 = (int)(Math.random() * 3 +1);
            question3 = (int)(Math.pow(question1, question2));
            System.out.println("How much is " + question1 + " raised to the power of " + question2 + " ?");
            System.out.println("Enter 0 to skip this question");
            evaluateUserAnswer();
        } while(userWantToPlay());
        finishGame();
    }//end of a method operatorPow()    
    
    public boolean userWantToPlay(){
        System.out.println("Do you want to play more? Y/N");
        Scanner userWantPlay = new Scanner(System.in);
        String wantPlay = userWantPlay.next();
        switch (wantPlay){
            case ("y"):
                userWant = true;
                break;
            case ("n"):
                userWant = false;
                break;
            default:
                System.out.println("Please enter Y/N");
                userWantToPlay();
        }
        return userWant;
    }//end of a method userWantToPlay()
    
    public void evaluateUserAnswer(){
    boolean want = true;
        while (want){
            try{
                Scanner scUserAnswer = new Scanner(System.in);
                int userAnswer = scUserAnswer.nextInt();
                if (userAnswer == question3){
                    System.out.println("Congrats! You are right!");
                    ++rightAnswers;
                    break;
                } else if (userAnswer == 0){
                        ++numberOfSkips;
                        break;
                    } else{
                        System.out.println("Ouch! Try again!");
                        System.out.println("Enter 0 to skip this question");
                        ++numberOfTries;
                    }
                } catch(java.util.InputMismatchException notANumber){
                    System.out.println("You have entered not a valid number");
                    System.out.println("Please enter valid answer");
            }
        }
    }//end of a method evaluateUserAnswer()
    
    public void finishGame(){
        System.out.println("Game over");
        if(rightAnswers > 1 && numberOfTries == 0 && numberOfSkips == 0){
            System.out.println("Your have scored " + rightAnswers + " right answers without wrong tries or skips!!!");
        } else{
            switch (rightAnswers){
                case 0:
                    System.out.println("Your have scored 0 right answers with " + numberOfTries + " wrong try(s) and " + numberOfSkips + " skip(s)!");
                    System.out.println("Go learn some math!");
                    break;
                case 1:
                    System.out.println("Your have scored 1 right answer with " + numberOfTries + " wrong try(s) and " + numberOfSkips + " skip(s)!");
                    break;
                default:
                    System.out.println("Your have scored " + rightAnswers + " right answers with " + numberOfTries + " wrong try(s) and " + numberOfSkips + " skip(s)!");
            }
        }
    }//end of a method finishGame()
}//end of a class TrainYourBrain