import javax.swing.JOptionPane;

public class Lab5 {

	public static void main(String[] args) {

		String prompt = “Enter a grade 0-100\n(Hit Cancel to abort)”;
		int x=0;
		String str;
		for (;;)
		{
			str = JOptionPane.showInputDialog(prompt);
			if (str==null || str.equals(""))
				break;
			x = Integer.parseInt(str);
			if (x>=0 && x<=100)	// input is valid.
				break;
			JOptionPane.showMessageDialog( null, "Invalid grade, try again");
		}
		if (str != null  && !str.equals(""))
			JOptionPane.showMessageDialog( null, "The grade is " + x);
	}
}