Question

I’m new to java, the nextLine(); doesn’t work once and it does all of the other times. I’m confused 🙁 I use eclipse in case you need to know.

    package tuna;
    import java.util.Scanner;

    public class Calculater {
        public static void main (String args []) {
            Scanner uno = new Scanner(System.in);
            System.out.println("How many differant numbers do you want to use? (up to four, minimum two)");
            double two = uno.nextDouble();
            if (two == 2){
                System.out.println("2");
                System.out.println("Enter first number: ");
                double fnum = uno.nextDouble();
                System.out.println(fnum);
                System.out.println("Enter second number: ");
                double snum = uno.nextDouble();
                System.out.println(snum);
                System.out.println("Enter number operation (Say plus, minus, divide or times. No capitials please)");
                String op = uno.nextLine();

. above the uno.nextLine doesn’t work. Why?

if (op.equals("plus")){
                        System.out.println(fnum + snum);

                    }


                }
                double three;
                double four;



            }



    }

EDIT: What I mean by ‘it doesn’t work’ is that after “Enter number operation (Say plus, minus, divide or times. No capitials please)” is printed in the output, I can’t type anything in. When you run it says how many numbers do you want? I type 2 and enter. Then it says enter first number. I say 1 and enter. Then it says enter second number. I say 1 and enter. Then it says what number operation. It doesn’t let you type even though there is a nextLine(); in there. If you add another nextLine(); in there you can type, but if you type plus, nothing happens, where it should print the first number add the second number.

Answer 1

If you input:

3.5<enter>
2<enter>
divide<enter>

Then uno.nextDouble(); consumes 3.5 and leaves

<enter>
2<enter>
divide<enter>

Then uno.nextDouble(); consumes <enter>2 and leaves

<enter>
divide<enter>

Next uno.nextLine(); just consumes <enter>. You need to call uno.nextLine(); again in order to consume the remaining divide<enter>.