Thread: Array and Loop?

Goal: To count the number of times each letter (a-z, both upper and lower case) appears in a file. Lower and upper case versions count as the same letter. So a's and A's both will be counted as a's. I am supposed to use an array

So I have three problems.
1. I'm not sure if I should do letters (a-z) for my array or numbers (0 - 25).
2. Would a while loop be the best? Or a for loop?
3. How do I combine the use of the scanner and the array in the loop?

This is my code so far:

/*
 * Count the number of times a letter 
 * 
 * @author Kristen Watson
 * @version 11/12/2012
 * 
 */
 
import java.util.Scanner;
import java.io.File;
 
public class LetterInventory{
    public final static String filename = "testFile.txt";
 
    public static void main(String[] args) {
        Scanner inputFile = null;
        try {
            inputFile = new Scanner(new File(filename));
        } catch (Exception e) {
            System.out.println("File could not be opened: " + filename);
            System.exit(0);
        }
 
        countOccurrences(inputFile);
        displayTable();
    }
 
 
    /*
     * constructor
     * inventory of letters with maximum of 26 different letters
     */
    public LetterInventory(){
        char []inventory = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i',
              'j', 'k','l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 
              'v', 'w', 'x', 'y', 'z'};  
 
    }
 
    /*
     * scanner takes information from the file and counts the letters 
     */
 
    public static void countOccurrences(Scanner file) {
 
         // file.next();
 
 
    }
 
 
 
    /*
     * output of the counted letters
     */
    public static void displayTable(){
        System.out.println("a:" );
        System.out.println("b:" );
        System.out.println("c:" );
        System.out.println("d:" );
        System.out.println("e:" );
        System.out.println("f:" );
        System.out.println("g:" );
        System.out.println("h:" );
        System.out.println("i:" );
        System.out.println("j:" );
        System.out.println("k:" );
        System.out.println("l:" );
        System.out.println("m:" );
        System.out.println("n:" );
        System.out.println("o:" );
        System.out.println("p:" );
        System.out.println("q:" );
        System.out.println("r:" );
        System.out.println("s:" );
        System.out.println("t:" );
        System.out.println("u:" );
        System.out.println("v:" );
        System.out.println("w:" );
        System.out.println("x:" );
        System.out.println("y:" );
        System.out.println("z:" );   
 
    }
 
 
 
    public static void resetInventory(){
 
 
    } 
}

And this is the drive that was provided:

*  It opens a test file and then uses a student written
 *  class called LetterInventory to count the number of
 *  times each letter occurs in the test file.
 * 
 * @author Clark Olson
 * @version 11/7/2012
 */
 
import java.util.Scanner;
import java.io.File;
 
public class LetterCounter {
 
    public final static String filename = "testFile.txt";
 
    // Driver to test LetterInventory class
    public static void main(String[] args) {
        Scanner inputFile = null;
        try {
            inputFile = new Scanner(new File(filename));
        } catch (Exception e) {
            System.out.println("File could not be opened: " + filename);
            System.exit(0);
        }
 
        LetterInventory inventory = new LetterInventory();
        inventory.countOccurrences(inputFile);
        inventory.displayTable();
        inventory.resetInventory();
    }
 
}