CountLetters.java

import java.util.Scanner;

// ****************************************************************
// CountLetters.java
//
// Reads a words from the standard input and prints the number of
// occurrences of each letter in that word.
//
// ****************************************************************
public class CountLetters {

	public static void main(String[] args) {
	
		int[] counts = new int[26];
		Scanner scan = new Scanner(System.in);

		//get word from user
		System.out.print("Enter a single word (letters only, please): ");
		String word = scan.nextLine();

		//convert to all upper case
		word = word.toUpperCase();
	
			//count frequency of each letter in string
			for (int i=0; i < word.length(); i++) {
    			try{
    				counts[word.charAt(i)-'A']++;
    			}
    			catch (ArrayIndexOutOfBoundsException problem) {
    				System.out.println("Contained characters other than letters, character was: " + (char)(Integer.parseInt(problem.getMessage()) + '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]);
			}
		}
	}
}