MostFrequentInSentence.java

//  Find the most frequent vowel and consonant in a String?

public class MostFrequentInSentence {

    /**
      * Program: MostFrequentInSentence.java
      * Purpose: Yahoo! Answers
      * Creator: Chris Clarke
      * Created: 26.05.2018
      */

    public static void main (String[] args) {

        int[] freq = new int[26];   // array holds frequency of each letter
        int vowels     =   0;   // maximum frequency of each vowel
        int consonants =   0;   // maximum frequency of each consonant
        char maxV      = ' ';   // vowel character appearing most often in sentence
        char maxC      = ' ';   // consonant character appearing most often in sentence
        char ch;        // current character in sentence
        int chNum      =   0;   // number 0-25 of current character in sentence

        String sentence = "How razorback-jumping frogs can level six piqued gymnasts";
        System.out.println ("The sentence is: \"" + sentence + "\"");
        String line = sentence.toLowerCase();
        for (int i = 0; i < line.length(); ++i) {
            ch = line.charAt(i);
            if (ch < 'a' || ch > 'z') continue; // if not a letter, start next loop
            chNum = (int) (ch-'a');     // 0-25
            freq[chNum]++;          // increment frequency for this letter
            if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') {
                if (freq[chNum] > vowels) {
                    vowels = freq[chNum];
                    maxV = ch;
                }
            } else {
                if (freq[chNum] > consonants) {
                    consonants = freq[chNum];
                    maxC = ch;
                }
            }
        }
        System.out.println("Vowel that appears most: " + maxV);
        System.out.println("Consonant that appears most: " + maxC);
    }
}