// ****************************************************************
//   CountLetters.java
//
//   Reads a series of letters from the keyboard and prints the
//   number of occurrences of each letter.
//
// ****************************************************************
import java.util.Scanner;
public class CountLetters
{
    public static void main(String[] args)
    {
       Scanner scan = new Scanner(System.in);
       String line;
       int[] counts = new int[26];

       //get user input
       System.out.print("Enter a sequence of letters (enter an empty line to stop): ");
       line = scan.nextLine();

       while (!line.equals(""))
       {
          //set all count array elements to 0
          for (int i=0; i < counts.length; i++)
            counts[i] = 0;

          //convert to all upper case
          line = line.toUpperCase();

          //counts the frequency of each letter in string
          for (int i=0; i < line.length(); i++)
             counts[line.charAt(i)-'A']++;

          //print frequencies
          System.out.println();
          for (int i=0; i < counts.length; i++)
             if (counts [i] != 0)
                System.out.println((char)(i +'A') + ": " + counts[i]);

          //get user input
          System.out.print("\nEnter a sequence of letters (enter an empty line to stop): ");
          line = scan.nextLine();

       }
    }
}