Java printing an array?

Question

I have an array:

private String[] gamesArray = new String[] {"spin", "tof"};

And when I start the program, I want the program to print the items in the array:

Please select a game: spin, tof.

This is my attempt:

import java.util.Scanner;

public class Main {

private Scanner console = new Scanner(System.in);
private Spin spin = new Spin();
private String input = "";
private String[] gamesArray = new String[] {"spin", "tof"};

public static void main (String[] args) {

    System.out.println("Welcome to the system!");

    for (String s : gamesArray) {

        System.out.println("Please select a game:" + s);

    }

}
}

Error:

src\Main.java:15: error: non-static variable gamesArray cannot be referenced fro
m a static context
                for (String s : gamesArray) {
                                ^

What is wrong?

Rather than making gamesArray a field, you could create the variable inside of your main method — mistahenry, Jun 24 '13 at 19:24
On a side note, this will not print what you intend. Rather it will print: Please select a game: spin Please select a game: tof — ardent, Jun 24 '13 at 19:32

score 3 · Accepted Answer · answered Jun 24 '13 at 19:23

3

You're trying to print an instance field without an instance. The main() method is static.

You could solve this by declaring gamesArray to be a static field. For example:

 private static final String[] gamesArray = new String[] {"spin", "tof"};

Alternatively, you could make an instance of the class Main(), and accessing the field through that.

 Main myMain = new Main();
 for (String s : myMain.gamesArray) {

Once you do one of those, you'll notice the output looks like this:

Please select a game:spin
Please select a game:tof

You may want the "Please select the game" to be outside the loop.

answered Jun 24 '13 at 19:23

Andy Thomas

84,978
11
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Thanks Andy, can you please link me to a place that explains everything about the difference between a regular int, String, other methods, and Statics + void methods? I've been searching the docs, couldn't really find what I want. – Jony Kale Jun 24 '13 at 19:25
@JonyKale, http://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html is a good place to start. – ardent Jun 24 '13 at 19:26
@JonyKale - Here's another: http://stackoverflow.com/questions/797964/what-is-the-exact-meaning-of-static-fields-in-java . As an example, consider a hypothetical class Human. The species name could be a static field. An individual's height could be an instance field. – Andy Thomas Jun 24 '13 at 19:30

Prasad Kharkar · Answer 2 · 2013-06-24T19:32:12.470

You need to create the object of class first

 Main obj = new Main();
 for(String s : obj.gamesArray){
       System.out.println("Please select a game:" + s);

 }

A static method or variable can be accessed directly from static method. If you declare the array as private static String[] gamesArray = new String[] {"spin", "tof"}; then you could have accessed it without creating the object of Main class
But you can access a static variable directly from an instance method because static variables are shared variables across all the instances.

If you want to access instance variables directly, then you can access them in instance methods and not static methods.

public class StaticNonStatic {

private static int staticVar;
private int instanceVar;

public void instanceMethod(){
    System.out.println(instanceVar);// instance variable accessed directly
    System.out.println(staticVar); // static variable accessed directly from instance method
}

public static staticMethod(){
    System.out.println(instnaceVar); // no this is wrong, can't access instance member from static block directly
    System.out.println(instnaceVar); // fair enough, accessing static member from static method directly
}

}

I like that name, `obj`, since it tells me it's an object and not a giraffe or a tuna fish. — David Conrad, Jun 24 '13 at 19:33

score 0 · Answer 3 · answered Jun 24 '13 at 19:24

0

GamesArray is an instance member of your class. Since main method is always static there is no instance of the class to get at gamesArray. Consider making gamesArray static

answered Jun 24 '13 at 19:24

aaronman

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Java printing an array?

3 Answers3