How to "throw an exception?"

[Ashley Kin]

Hello, I wrote this code that takes values as input from a user until a negative number is entered, and then prints the average of those values, not including the negative number.
I need to figure out how to not print an average if the first number a user inputs is negative. I think I should "throw an exception," but I'm not really sure how to go about that.
Thanks!

public static void printAverage() 
	{	
		Scanner console = new Scanner(System.in);
		int sum = 0;
		int count = 0;
		System.out.print("Enter a number (negative number to quit): ");
		int number = console.nextInt();
		if (number < 0)
		{
			System.out.println("No average.");
		} else
		{
			while (number > 0)
			{
				sum = sum + number;
				count++;
				System.out.print("Enter a number (negatives number to quit): ");
				number = console.nextInt();
			}
		}

[Paul Clapham]

Not really sure? Then since you want to know about exceptions, your google keywords should be "java exception tutorial".

The first link you get back should be Oracle's tutorial (have a look at the URL to make sure). Read it: Lesson: Exceptions.