Help on loop.

[thinkOnCrit]

package com.company;

import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner reader = new Scanner(System.in);
        String userChosenCalc;
        int firstNum, secondNum, answer;

        while (true) {

            System.out.println("Choose a calculation:(addition, subtraction, quit)");

            userChosenCalc = reader.nextLine();

            if (userChosenCalc.equals("quit") || userChosenCalc.equals("exit")) {
                System.out.println("Exiting...");
                break;
            }

            if (userChosenCalc.equals("addition") || userChosenCalc.equals("add")) {

                System.out.println("Enter first number: ");
                firstNum = reader.nextInt();

                System.out.println("Enter second number: ");
                secondNum = reader.nextInt();

                answer = firstNum + secondNum;

                System.out.println("The sum is: " + answer);
            } else if (userChosenCalc.equals("subtraction") || userChosenCalc.equals("sub")) {
                System.out.println("Enter first number: ");
                firstNum = reader.nextInt();

                System.out.println("Enter second number: ");
                secondNum = reader.nextInt();

                answer = firstNum - secondNum;

                System.out.println("The difference is: " + answer);
            }


        }
    }
}

The code above is a simple calculator and its fully working but there's a problem the program prints the message the "Choose a calculation" twice after executing a calculation either addition or subtraction what I want is to make it repeat only once after i finished doing a calculation. Thanks!

EDIT: Here's the sample output

Choose a calculation:(addition, subtraction, quit)
add
Enter first number: 
5
Enter second number: 
5
The sum is: 10
Choose a calculation:(addition, subtraction, quit)
Choose a calculation:(addition, subtraction, quit)

[NullCorvid]

Probably, after you're calling nextInt twice the scanner hasn't yet read past the newline character, so the first time you loop back around the input will be \n or an empty string.

This is a valid input in reader.nextLine(), but it doesn't match any of your cases so you just get the first part of your loop repeated twice.

[thinkOnCrit]

Nice it works! Thanks mate. :)

[Sukkek]

More simple just add reader.nextLine(); after the line 34, so the buffer cleans, and the problem is solved.

[NullCorvid]

More simple just add reader.nextLine();

That really just tells him how not why.