Question

Write a program to accept a sentence which may be terminated by either ‘.’, ‘?’ or ‘!’ only. The words are to be separated by a single blank space and are in uppercase.

Perform the following tasks:

a) Check for the validity of the accepted sentence.
b) Convert the non-palindrome words of the sentence into palindrome words by concatenating the word by its reverse (excluding the last character).

Example: The reverse of the word HELP would be LEH (omitting the last alphabet) and by concatenating both, the new palindrome word is HELPLEH. Thus, the word HELP becomes HELPLEH.

Note: The words which end with repeated alphabets, for example ABB would become ABBA and not ABBBA and XAZZZ becomes XAZZZAX.

[Palindrome word: Spells same from either side. Example: DAD, MADAM etc.]

c) Display the original sentence along with the converted sentence.

Test your program for the following data and some random data:

Example 1:
INPUT: THE BIRD IS FLYING.
OUTPUT:
THE BIRD IS FLYING.
THEHT BIRDRIB ISI FLYINGNIYLF
Example 2:
INPUT: IS THE WATER LEVEL RISING?
OUTPUT:
IS THE WATER LEVEL RISING?
ISI THEHT WATERETAW LEVEL RISINGNISIR
Example 3:
INPUT: THIS MOBILE APP LOOKS FINE.
OUTPUT:
THIS MOBILE APP LOOKS FINE.
THISIHT MOBILELIBOM APPA LOOKSKOOL FINENIF
Example 4:
INPUT: YOU MUST BE CRAZY#
OUTPUT:
INVALID INPUT

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Code

import java.util.Scanner;
import java.util.StringTokenizer;
public class PalindromeSentence
{

    public static boolean isPalindrome(String w)
    {
        int i=0;
        String r = "";
        for(i = w.length() - 1; i >= 0; i--)
        {
            r += w.charAt(i);
        }
        return (w.equalsIgnoreCase(r));
    }


    public static String generate(String w)
    {
        int i=0;
        String r ="";
        for(i = w.length() - 2; i >= 0; i--)
        {
            r += w.charAt(i);
        }
        w = w.substring(0, w.length());
        return w + r;
    }


    public static void main(String args[])
    {
        int i=0,count=0;
        char ch=' ';

        Scanner sc=new Scanner(System.in);
        System.out.print("Sentence: ");
        String sen = sc.nextLine().toUpperCase();
        ch = sen.charAt(sen.length() - 1);
        if(ch != '.' && ch != '?' && ch != '!')
        {
            System.out.println("INVALID INPUT");
            return;
        }
        StringTokenizer st = new StringTokenizer(sen, " ?.!,");
        count = st.countTokens();
        String newSen ="";
        for(i = 1; i <= count; i++)
        {
            String word = st.nextToken();
            if(isPalindrome(word))
            {
                newSen += word + " ";
            }
            else
            {
                newSen += generate(word) + " ";
            }
        }
        System.out.println(sen);
        System.out.println(newSen);
    }


}