Parsing a string to an int while receiving user input?

**happyxcrab** · May 10th, 2011, 03:05 AM

package exercise2;
import java.util.Scanner;
 
public class Exercise2 {
 
    Scanner user_input = new Scanner(System.in);
 
 
    public static void main(String[] args) {
 
 
        System.out.println ("Pick a number from 0 to 100");
 
 
        String number = user_input.next(); 
       int pn =Integer.parseInt(number.trim());
 
 
    } 
}

I keep getting this error on the "String number = user_input.next();" line.
non-static variable user_input cannot be referenced from a static context

Any help? I've looked online and I get lots of help for assigning variables, but not with user input.

**KevinWorkman** · May 10th, 2011, 07:52 AM

This problem has nothing to do with user input. The main() method is a static method, which means it can only access static methods and variables. user_input is not a static variable.

Your options are to create an instance of Exercise2 and access user_input form within it, or to make user_input static.

**happyxcrab** · May 10th, 2011, 05:38 PM

Is there any chance that I could get pointed in the right direction? I'm brand new at this.
Thank you for the help though

**KevinWorkman** · May 11th, 2011, 07:44 AM

I'd say google is your friend here- you must understand what the static keyword does.

Basically: normal, non-static variables and methods (like your user_input variable) must be a member of a specific instance of a class. For example, it doesn't make sense for there to be a JFrame height or width without an instance of JFrame to have a height or width.

However, static variables and methods (like the main method) do not need to be a member of a specific instance of a class. So you don't need to create an instance of Exercise2 before calling main (how would you?). System.out is another example of a static variable.

The confusion in your case is caused by mixing static and non-static. While you're "in" main, you aren't working from a specific instance of Exercise2. So when you try to use user_input from the main method, it's like trying to use a JFrame's height or width without creating a JFrame first.

You should probably create an instance of Exercise2, mostly because overusing the static keyword is a really bad practice to habitualize. But you could also make user_input static.

**happyxcrab** · May 11th, 2011, 05:38 PM

Thank you! I'll be sure to google everything in the world!! haha

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