CMSC 256 Project 1

PA1KDB.java

/* Student: Kevin Barbour
 * Course: Computer Science 256
 * Professor: Dr. Parker
 * Assignment 1
 */

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Scanner;
import java.lang.reflect.Array;
import java.lang.Character;

/* Class PA1KDB
 *
 * Analyzes a text file and prints the number of times each unique letter
 * occured in the file.
 */
public class PA1KDB 
{
    /* method main
     *
     * Takes the name of a text file as an argument, cycles through each character in the
     * file counting the occurances of each unique letter, then prints a formatted
     * table showing how many times each occured.
     */
    public static void main(String[] args)
    {
        // Make sure an argument was given
        if(args.length == 0){
            System.out.println("No argument given. Run as 'java PA1KDB <filename>'");
            System.exit(0);
        }

        // Get text from file as string
        String file_name = args[0];
        String file_string = readFile(file_name);

        // Make array of characters from string
        char file_chars[] = file_string.toCharArray();

        // Make array to keep count of each letter (indexed at <ascii code for letter> - 'A')
        int char_counts[] = new int[58];

        // Loop through characters adding one to each count when a letter is found
        for(int i = 0; i < Array.getLength(file_chars); i++) {
            // Check if the character is actually a letter
            if(Character.isLetter(file_chars[i])) {
                // Add to count for letter in array
                    char_counts[file_chars[i] -'A']++;
            }
        }

        System.out.println("CMSC 256 Project #1 - K. Barbour\n");
        System.out.println("Input file:" + file_name);
        System.out.println("Contents:\n" + file_string);
        printResults(char_counts);
    }// main()

    /* method readFile
     *
     * Takes the name of a file as a string input. Creates a string from the text
     * in the file, and returns the string.
     */
    static String readFile(String file_name) throws FileNotFoundException, IOException
    {
        File input_file = new File(file_name);
        Scanner file_reader = new Scanner(input_file);

        // Make string from file
        String file_string = file_reader.useDelimiter("\\Z").next();

        return file_string;
    }// readFile()

    /* method printResults
     *
     * Takes an array of integers as input. Loops through each index of the array
     * printing the occurances of the character if any.
     */
    static void printResults(int[] char_counts)
    {
        
        System.out.println("\nLetter Count\n------ -----");

        // Print lowercase results
        for(int i = 32; i < 58; i++) {
            //if(low_char_counts[i] > 0) {
            if((char_counts[i]) > 0) {
                System.out.printf("   %c\t%d\n", (char) (i + 'A'), char_counts[i]);
            }
        }

        // Print uppercase results
        for(int i = 0; i < 26; i++)
            if((char_counts[i]) > 0) {
                System.out.printf("   %c\t%d\n", (char) (i + 'A'), char_counts[i]);
            }
    }// printResults()
}// class PA1KDB