Exception Handling help

[MZA]

Hello all.

I have to trying to write a program that takes user-input floating point numbers and adds them together. If the user enters a value that isn't a number, it gives them a second chance to enter some, and if they don't it then quits reading input. And this is where I'm goofed. My exception handling of the improper inputs is messing me up. Any advice on a good way to fix them?

Here's my code:

import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.Scanner;

public class RealAdder {
	private static ArrayList<Double> numArray = new ArrayList<Double>();
	private static double sum = 0;//compute sum()
	private static final String STOP_CHAR = "~";
	private static final int EXIT_NO_VALUES = 0;
	private static final int MAX_ATTEMPTS = 2;
	private static int attempts = 0;
	private static int an = 0; //Last array;


	/**
	 * @param args
	 * Usage []
	 * @return 
	 */
	public static void main(String[] args) {
		// Get user input values
		getNumbers();
		
		// Compute the sum of the numbers
		computeSum();
		
		// Output the sum
		printSum();
	}
	
	/**
	 *@param InputMismatchException
	 * 
	 * 
	 */
	private static void getNumbers() {
		boolean done = false;
		while (!done){
			Scanner in = new Scanner(System.in);
			try{ 
				System.out.println("Enter a floating-point variable. Type '~' when finished. ");
				System.out.println("try1");
				while(in.hasNextDouble()){
					System.out.println("in.hasNextDouble");
					numArray.add(in.nextDouble());
					an++;
				}
				try{
					System.out.println("try2");
					if(STOP_CHAR.equals(in.next(STOP_CHAR))){
						System.out.println("try2/if");
						System.out.println("Stop Char");
						done=true;
					}
				}
				finally{
					System.out.println("Finally");
					in.close();
					if(attempts>=MAX_ATTEMPTS){
						System.out.println("Maximum attempts has been reached. Goodbye.");
						System.exit(0);
					}

				}
			}
			catch(InputMismatchException exception){
				System.out.println("Catch statement 1 activated");
				System.out.println("Not a floating-point variable");
				attempts++;
			}
			catch(IndexOutOfBoundsException exception){
				System.out.println("Catch statement 2 activated");
				attempts++;
			}
			
		}
	}	
		
	private static void computeSum() {
		System.out.println("ComputeSum");
		System.out.println("NumArraySize: " +an);
		if(numArray.isEmpty()){
			System.out.println("Array Empty");
			System.exit(EXIT_NO_VALUES);
		}
		for(int a1 = 0; a1 < numArray.size(); a1++){
			sum = sum + numArray.get(a1);
		}	
	}

	private static void printSum() {
		System.out.println("Sum: " +sum 
				+"\nArrayList:" +numArray);
	}//End printSum
}//End Main

[Tolls]

You haven't actually said what problem you're having.

[Aseem]

use NumberFormatException which takes specific data type. If you try to enter String for number, it will throw exception.

[thomasdevos]

Hello MAZ,
acutally, you have done a great code, all you need to do is just modify this line:

					if(STOP_CHAR.equals(in.next(STOP_CHAR))){

into

					if(STOP_CHAR.equals(in.next())){

you world is in peace.

here is some test on your program:

Enter a floating-point variable. Type '~' when finished. 
try1
1
in.hasNextDouble
2
in.hasNextDouble
3
in.hasNextDouble
4
in.hasNextDouble
~
try2
try2/if
Stop Char
Finally
ComputeSum
NumArraySize: 4
Sum: 10.0
ArrayList:[1.0, 2.0, 3.0, 4.0]

and below is runnable code modified from yours:

import java.util.ArrayList;
import java.util.InputMismatchException;
import java.util.Scanner;

public class ExceptionHandle {
	private static ArrayList<Double> numArray = new ArrayList<Double>();
	private static double sum = 0;//compute sum()
	private static final String STOP_CHAR = "~";
	private static final int EXIT_NO_VALUES = 0;
	private static final int MAX_ATTEMPTS = 2;
	private static int attempts = 0;
	private static int an = 0; //Last array;


	/**
	 * @param args
	 * Usage []
	 * @return 
	 */
	public static void main(String[] args) {
		// Get user input values
		getNumbers();
		
		// Compute the sum of the numbers
		computeSum();
		
		// Output the sum
		printSum();
	}
	
	/**
	 *@param InputMismatchException
	 * 
	 * 
	 */
	private static void getNumbers() {
		boolean done = false;
		while (!done){
			Scanner in = new Scanner(System.in);
			try{ 
				System.out.println("Enter a floating-point variable. Type '~' when finished. ");
				System.out.println("try1");
				while(in.hasNextDouble()){
					System.out.println("in.hasNextDouble");
					numArray.add(in.nextDouble());
					an++;
				}
				try{
					System.out.println("try2");
					if(STOP_CHAR.equals(in.next())){
						System.out.println("try2/if");
						System.out.println("Stop Char");
						done=true;
					}
				}
				finally{
					System.out.println("Finally");
					in.close();
					if(attempts>=MAX_ATTEMPTS){
						System.out.println("Maximum attempts has been reached. Goodbye.");
						System.exit(0);
					}

				}
			}
			catch(InputMismatchException exception){
				System.out.println("Catch statement 1 activated");
				System.out.println("Not a floating-point variable");
				attempts++;
			}
			catch(IndexOutOfBoundsException exception){
				System.out.println("Catch statement 2 activated");
				attempts++;
			}
			
		}
	}	
		
	private static void computeSum() {
		System.out.println("ComputeSum");
		System.out.println("NumArraySize: " +an);
		if(numArray.isEmpty()){
			System.out.println("Array Empty");
			System.exit(EXIT_NO_VALUES);
		}
		for(int a1 = 0; a1 < numArray.size(); a1++){
			sum = sum + numArray.get(a1);
		}	
	}

	private static void printSum() {
		System.out.println("Sum: " +sum 
				+"\nArrayList:" +numArray);
	}//End printSum
}//End Main

i hope you can learn something from by comparation.
good luck