Grade Average Program - Hit Button Reseved For Calculations

I have written a simple grade average program. This is my code:

package programs;
 import java.util.Scanner;
 public class GradeAverage {
 public static void main(String[] args) {
 Scanner input = new Scanner(System.in);
int number;
int counter = 0;
int grade;
 
[Code] ....

Now the program is working just fine but what I don't like about it is the fact that you have to enter the number of grades before entering the grades. What I would prefer is to write your grades, hit some button that is reserved for calculating the average and then get the output.