StringColumnWords

import java.util.Scanner;
public class Practice_7_2
{
   public static void main(String[] args)
   {
   //declare variables
   char ch;
   int end, num = 1;
   //do while loop allows user to go again
   do
   {
   //prompt user and get input string
   System.out.print("Enter a string: ");
   Scanner input = new Scanner(System.in);
   String sentence = input.nextLine();
   //prints title for first word
   System.out.print("Word #1:\t");
   //for loop runs for length of string
   for (int i = 0; i < sentence.length(); i++)
   {
   //ch is a character in the string
   ch = sentence.charAt(i);
   //if statement prints letters untiil there is white space
   if ((ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))
      {
         System.out.print(ch);
               }
         else
         {
            //increments the word number and prints word
            num++;
            System.out.print("\nWord #" + num + ":\t");
         }          
   }
   //asks user if they want to go again and ends if 0 is typed
   System.out.print("\nDo you want to go again? ");
   end = input.nextInt();
   //resets word number to 1
   num = 1;
   }
   while (end != 0);
   }
}

http://math.hws.edu/eck/cs124/javanotes4/c3/ex-3-4-answer.html

This post helped me somewhat, although I didn't want to use the character method because we have not covered that in class yet and I would like to be able to solve each problem with the knowledge introduced so far.

This program has a problem if there is any punctuation, so I need to figure out how commas and periods could be covered in the if statement simply.