Thread: Problem while implementing a basic user interface menu

Hey, I need to create a basic user interface menu. My code complies, however it doesnt seem to work properly. Heres the code-

import java.util.*;
 
public class Program3
{
	public static void main(String[ ] args)
	{
		//declare variables
 
		String Paren = "";
		ParenExpression fullParen = new ParenExpression(Paren);
		Scanner kb = new Scanner(System.in);
		int response;
 
		//do while loop that controls program
		System.out.println("Welcome to the Program3");
 
		do
		{
			//show the menu
			System.out.println("\n\nChoose an option");
			System.out.println("\t1\tCreate a new fully parenthesized expression");
			System.out.println("\t2\tPrint the expression");
			System.out.println("\t3\tPrint what it evaluates to");
			System.out.println("\t4\tPrint the postfix equivalent");
			System.out.println("\t5\tQuit");
 
			//get the user response to menu
			try
			{
				response = kb.nextInt();   //get it
			}
			catch(InputMismatchException e)
			{
				response = -1;    //something illegal
				kb.nextLine();   //flush it
			}
 
			//do a logic "branch" depending on their response
			try
			{
 
				if (response == 1)
				{
 
					//prompt user
					System.out.print("\nPlease enter a fully parenthesized expression: ");
					Paren = kb.nextLine();
					kb.nextLine();
					fullParen = new ParenExpression(Paren);
 
				}
				else if (response == 2)
				{
					System.out.println(fullParen);
				}
				else if (response == 3)
				{
					System.out.println(fullParen.evaluate());
				}
				else if (response == 4)
				{
					System.out.println(fullParen.asPostfix());
				}
				else
					System.out.println("\nInvalid input - try again");
			}
 
			catch (Throwable theException)  //...catches everything (since every one is a subclass of Throwable)
			{
				System.out.println("got something - " + theException);
				theException.printStackTrace();       //prints the calling sequence up to the exception
			}
		}
		while (response != 5);
	}
}

I think the problem might come from the flushing in the first response around lines 46-49, however I'm not sure. Those lines of code are -

					System.out.print("\nPlease enter a fully parenthesized expression: ");
					Paren = kb.nextLine();
					kb.nextLine();
					fullParen = new ParenExpression(Paren);

Any tips would be appreciated