Trying to create simple java menu, but its not working

Question

This is the code. I gives me an error where the switch is. Please help. Maybe a link to a site where i can learn this.

public class Main{
public static void main(String[] args) {
    int swValue;

    System.out.println("***************************************Menu***************************************");
    System.out.println("Spauskite 1 jei norite atspauzdinti programje sukurtu objektu sarasus");
    System.out.println("Spauskite 2 jei norite sukurti naujus objektus, ju duomenis ivedant is klavieturos");
    System.out.println("Spauskite 3 jei norite iskviesti objektu metodus");

    switch (swValue) {
    case 1: System.out.println("1 Selected");
        break;
    case 2: System.out.println("2 Selected");
        break;
    case 3: System.out.println("3 Selected");
        break;
    default: System.out.println("Invalis selection");
    break;
    }

not much of a menu if the user can't choose an option first (aka: ask the user and initialize swValue with whatever the user tells you) — Julián Urbano
– Julián Urbano, Commented Dec 10, 2013 at 18:18

rgettman · Accepted Answer · 2013-12-10 18:15:25Z

2

It is a compiler error to use a local variable before it's initialized, and you didn't initialize it.

It looks like you will want to read the user input and initialize swValue before the switch statement.

answered Dec 10, 2013 at 18:15

rgettman

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3 Comments

user3088057 Over a year ago

Can u give me an example how to fix this?

rgettman Over a year ago

There are many ways, but two off the top of my head: 1) Initialize it to some value with int swValue = 0;, but that's not very useful here. 2) Use a Scanner to read the user input and assign the value to swValue.

rgettman Over a year ago

A few more ways: 3) Use a BufferedReader to read user input, converting it to an int with Integer.parseInt. 4) Read a command-line parameter in the args parameter of main and convert it to an int. 5) Use JOptionPane to ask the user via a dialog box and convert the answer to an int.

JustBrenkman · Accepted Answer · 2013-12-10 18:23:27Z

1

Try creating some kind of input reading;

    //print out menu options

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    try {
       swValue = Integer.parseInt(br.readLine());
    } catch (IOException ioe) {
       ioe.printStackTrace();
    }

    //switching code

answered Dec 10, 2013 at 18:23

JustBrenkman

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Comments

Sam Fischer · Accepted Answer · 2013-12-10 18:18:17Z

0

swValue isn't initialised i.e. there is not value assigned to it. So, how can you compare it to anything ?

If you want to get a value from the user, you can do either :

Accept swValue as a parameter :

void main(String[] args, int swValue)
Use the Scanner or BufferedReader classes to get input at run-time.

answered Dec 10, 2013 at 18:18

Sam Fischer

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