Java Programs - Solved 2016 Practical Paper ISC Computer Science

import java.io.*;
class Vowels{
    public static void main(String args[])
    throws IOException{
        InputStreamReader in = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(in);
        System.out.print("Sentence: ");
        String s = br.readLine();
        s = s.trim();
        s = s.toUpperCase();
        int len = s.length();
        char last = s.charAt(len - 1);
        if(last != '.' && last != '?' && last != '!'){
            System.out.println("INVALID INPUT");
            return;
        }

        String word = new String();
        String v = new String();
        String nv = new String();
        int count = 0;
        for(int i = 0; i < len; i++){
            char ch = s.charAt(i);
            switch(ch){
                case ' ':
                case '.':
                case '?':
                case '!':

                if(word.length() > 0 && testWord(word)){
                    count++;
                    v += word + " ";
                }
                else if(word.length() > 0)
                    nv += word + " ";
                word = new String();
                break;
                default:
                word += ch;
            }
        }

        System.out.println("NUMBER OF WORDS BEGINNING AND ENDING WITH A VOWEL = " + count);
        System.out.println(v + nv);
    }
    public static boolean testWord(String w){
        int len = w.length();
        char first = w.charAt(0);
        char last = w.charAt(len - 1);
        if(isVowel(first) && isVowel(last))
            return true;
        return false;
    }

    public static boolean isVowel(char ch){
        switch(ch){
            case 'A':
            case 'E':
            case 'I':
            case 'O':
            case 'U':
            return true;
            default:
            return false;
        }
    }
}