Java Loop from user input to repeat process?

Question

I am very new to Java Programming, I have been given a task to work out from user input the easter date for a given year and then to ask if the user would like to input another year to calculate another easter date. What I don't understand is how to create a loop from the second input box ("Noch eine Berechnung? (J/N)") that repeats the entire process again. My code is this:

import javax.swing.JOptionPane;

public class Osterberechnung_ohne_schleife {

 public static void main(String[] args) {


  String sJahrEingabe = JOptionPane.showInputDialog("Bitte Jahr eingeben:");


  int iJahr = Integer.parseInt(sJahrEingabe);

  int iP = iJahr / 100;
  int iQ = iP / 3;
  int iR = iQ / 4;
  int iX = (15 + iP - iQ - iR) % 30;
  int iY = (iP + 4 - iR) % 7;
  int iA = iJahr % 19;
  int iB = iJahr % 4;
  int iC = iJahr % 7;
  int iD = (19 * iA + iX) % 30;
  int iE = (2 * iB + 4 * iC + 6 * iD + iY) % 7;



  if ((iD == 29) && (iE == 6)) {

   System.out.println("Ausgabe: Ostern ist am 19.April");

  } else if ((iD == 28) && (iE == 6)) {

   System.out.println("Ausgabe: Ostern ist am 18.April");

  } else if ((22 + iD + iE) <= 31) {

   System.out.println("Ausgabe: Ostern ist am " + (22 + iD + iE) + ".März");

  } else {

   System.out.println("Ausgabe: Ostern ist am " + (iD + iE - 9) + ".April");

  }

  {

   String sNochJahr = JOptionPane.showInputDialog("Noch eine Berechnung? (J/N)");

  }


 }

}

Thanks in advance for your help.

Try putting your whole code in a WHILE loop. If user enters 'N', then break out of that loop — Hans
– Hans, Commented Nov 17, 2017 at 13:30
Put the code that does the computation in a function, then create a loop that will call it as long as then answer is J. — StephaneM
– StephaneM, Commented Nov 17, 2017 at 13:32

achAmháin · Accepted Answer · 2017-11-22 09:26:09Z

1

Surround your code with a do...while loop and keep going as long as sNochJahr is J.

do {
...
} while (sNochJahr.equals("J"));

or while sNochJahr is not N.

while (!sNochJahr.equals("N"));

edited Nov 22, 2017 at 9:26

answered Nov 17, 2017 at 13:33

achAmháin

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4 Comments

R.Buckley Over a year ago

I tried to put the whole code into a do...while loop, however the while sNochJahr cannot be resolved because the sNochjahr variable is within the do...while code. What i don't understand is how to make the do...while loop determined by the user input within the code.

R.Buckley Over a year ago

do { if ((iD==29) && (iE==6)) { System.out.println("Ausgabe: Ostern ist am 19.April"); } else if ((iD==28) && (iE==6)) { System.out.println("Ausgabe: Ostern ist am 18.April"); } else if ((22 +iD + iE) <= 31) { System.out.println("Ausgabe: Ostern ist am " + (22 + iD + iE) + ".März"); } else { System.out.println("Ausgabe: Ostern ist am " + (iD + iE - 9) + ".April"); } String sNochJahr = JOptionPane.showInputDialog("Noch eine Berechnung? (J/N)"); } while(sNochJahr.equals("J")); } }

achAmháin Over a year ago

Copy the code from that link there. Don't mind the error it's showing on that site; it's to do with JOptionPane.

R.Buckley Over a year ago

Thank you very much, it worked. Thanks for explaining, I understand now what I was doing wrong.

Yasin · Accepted Answer · 2017-11-17 13:33:44Z

Youre saving the response of the user in String sNochJahr, but not evaluating it. I would suggest something like this:

String sNochJahr = "J"

while (sNochJahr.equals("J")) {
      String sJahrEingabe = JOptionPane.showInputDialog("Bitte Jahr eingeben:");


    int iJahr = Integer.parseInt(sJahrEingabe);

    int iP = iJahr / 100;
    int iQ = iP / 3;
    int iR = iQ / 4;
    int iX = (15 + iP - iQ - iR)%30;
    int iY = (iP + 4 - iR)%7;
    int iA = iJahr % 19;
    int iB = iJahr % 4;
    int iC = iJahr % 7;
    int iD = (19 * iA + iX)%30;
    int iE = (2 * iB + 4 * iC + 6 * iD + iY)%7;



    if ((iD==29) && (iE==6)) {

        System.out.println("Ausgabe: Ostern ist am 19.April");

    } else if ((iD==28) && (iE==6)) {

        System.out.println("Ausgabe: Ostern ist am 18.April");

    } else if ((22 +iD + iE) <= 31) {

        System.out.println("Ausgabe: Ostern ist am " + (22 + iD + iE) + ".März");

    } else {

        System.out.println("Ausgabe: Ostern ist am " + (iD + iE - 9) + ".April");

    }

    {

    String sNochJahr = JOptionPane.showInputDialog("Noch eine Berechnung? (J/N)");

        }
}

If the user inputs "N" then, the code breaks out of the while-loop.

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