How to exit the program with a letter

Question

I am attempting to create a program thtat does some processing and exits when a given letter is typed.

//1.00usd = .727751euro
int reset = 0;
while(reset == 0)
{
    double euro;
    double ems;

    String input = JOptionPane.showInputDialog(null,"Enter Amount of US Dollar: ");

    ems = Double.parseDouble(input);

    if (ems < 0)
    {
        JOptionPane.showMessageDialog(null, "Please enter a real amount of money");
        reset = 0;
    }

    if (ems >= 0)
    {
        euro = .727751;
        ems = ems*euro;
        ems = ems*100;
        ems = Math.round(ems);      
        ems = ems/100;

        JOptionPane.showMessageDialog(null,"Amount in euros: € " + ems);
    }
}

This program is to convert usd to euro and I wanted to know how I can make the program exit when entering the letter "Q".

This is for a an object class so I'm still learning.

Answer 1

Something like

String input = JOptionPane.showInputDialog(null,"Enter Amount of US Dollar: ");

if( input.equals("Q") ) // but the case is important here
{
    System.out.println("Bye bye");
    System.exit(0);
}
ems = Double.parseDouble(input);

Answer 2

If your question is "how to exit the program", you can call

System.exit(0);

when the user presses a key. If you just want to "quit" the loop you're in, manage to get the condition true, or use "break" (but you should not need it in your case).

Answer 3

Add this if statement in the while loop.

if(inputString.equalsIgnoreCase("q")) {
    System.exit(0);
}