ArrayIndexOutofBounds Exception

[atul.goldenstring]

Hi,
I am new to java..


please help...


public class atul{
public static void main(String[] args) {
System.out.println("Addition of two numbers!");
int a = Integer.parseInt(args[0]);
int b = Integer.parseInt(args[1]);
int sum = a + b;
System.out.println("Sum: " + sum);
}
}

Its giving the "ArrayOutofBounds Exception". Pls help..

I am using JDK 1.6

[Cemi]

I believe this is because your array is undefined, you have no element in args[0] and args[1].

[Tolls]

Yep.
What's the command you're calling?
"java atul" then what?

[FlyNn]

public class atul()
{
    public static void main(String[] args) {

       //Define array of type int
       //Add values to the array

        System.out.println("Addition of two numbers!");

        int a = args[0];
        int b = args[1];
        int sum = a + b;
        System.out.println("Sum: " + sum);
     }
}

[m00nchile]

Before you execute a program that requires user to input command line parameters, it's always a good idea to add a check to see if they were entered correctly, for example:

public class CmdPar {
  public static void main(String[] args) {
    if(args.length == 0) {
      System.out.pritln("Usage: java CmdPar param1 param2");
      System.exit(1);
    }
    //execute the program now that you know args is initialized
}

[Tolls]

public class atul()
{
...stuff...
}

How does that help?

[FlyNn]

How does that help?

I put comments in to what is needed to make it work... :confused:

[Tolls]

Still doesn't solve his problem, which is that "args" is either empty or has only one argument in it.

[FlyNn]

Before you execute a program that requires user to input command line parameters, it's always a good idea to add a check to see if they were entered correctly, for example:

public class CmdPar {
  public static void main(String[] args) {
    if(args.length == 0) {
      System.out.pritln("Usage: java CmdPar param1 param2");
      System.exit(1);
    }
    //execute the program now that you know args is initialized
}

I have never seen this sort of thing before. So this is to be used just if you are going to run the file using cmd? At what point args will not get initialized?

[j2me64]

if you expect exactly to numbers as arguments then use

import java.text.ParseException;

public class atul {
	public static void main(String[] args) {
		if (args.length != 2) {
			System.out.println("Usage: java atul number1 number2");
			System.exit(1);
		}

		try {
			int a = Integer.parseInt(args[0]);
			int b = Integer.parseInt(args[1]);
		} catch (NumberFormatException nfe) {
			System.out.println("You entered invalid numbers, retry.");
		}
	}
}

the parse method can throw an exception so that's why you should use a try-catch block.

[atul.goldenstring]

Thanks people. Really appreciate that help.