// CountLettersInArray.java: Count occurrences of each letter in
// in the array
public class CountLettersInArray {
  /** Main method */
  public static void main(String args[]) {
    // Declare and create an array
    char[] chars = createArray();
    
    // Display the array
    System.out.println("The lowercase letters are:");
    displayArray(chars);
    
    // Count the occurrences of each letter
    int[] counts = countLetters(chars);
   
    // Display counts
    System.out.println();
    System.out.println("The occurrences of each letter are:");
    displayCounts(counts);
    
    // Display mean and standard deviation of the counts
    System.out.println("\n\nMean is " + Deviation.mean(counts));
    System.out.println("Standard deviation is " + 
      Deviation.deviation(counts));
  }
  
  /** Create an array of characters */
  public static char[] createArray() {
    // Declare an array of characters and create it
    char[] chars = new char[100];
    
    // Create lowercase letters randomly and assign 
    // them to the array
    for (int i = 0; i < chars.length; i++) 
      chars[i] = RandomCharacter.getRandomChar('a', 'z');
    
    // Return the array
    return chars;
  }   
  
  /** Display the array of characters */
  public static void displayArray(char[] chars) {
    // Display the characters in the array 20 on each line
    for (int i = 0; i < chars.length; i++) {
      if ((i + 1) % 20 == 0)
        System.out.println(chars[i] + " ");
      else
        System.out.print(chars[i] + " ");
    }
  }
  
  /** Count the occurrences of each letter */
  public static int[] countLetters(char[] chars) {
    // Declare and create an array of 26 int
    int[] counts = new int[26];
    
    // For each lowercase letter in the array, count it
    for (int i = 0; i < chars.length; i++) 
      counts[chars[i] - 'a']++;
    
    return counts;
  }
  
  /** Display counts */
  public static void displayCounts(int[] counts) {
    for (int i = 0; i < counts.length; i++) {
      if ((i + 1) % 10 == 0) 
        System.out.println(counts[i] + " " + (char)(i + 'a'));
      else 
        System.out.print(counts[i] + " " + (char)(i + 'a') + " ");
    }
  }
}