Question

This is a java question

A palindrome is a word or phrase that reads the same forward and backward, ignoring blanks and punctuations, and considering uppercase and lowercase versions of the same letter to be equal. For example, the following are palindromes:

warts n straw
radar
Able was I ere I saw Elba
tacocat

Write a program named Palindrome.java that will accept a file (file name) from the command argument list and decide whether each line in the file is a palindrome. Then output the string of each line, followed by True if the string is a palindrome and False otherwise.

Note: data file palindrome.txt is provided for testing purpose. You may use this file to text your program.

Sample output:
Able was I ere I saw Elba       True
warts n straw   True
This is not a palindrome!  False
Java      False

Answer 1

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Palindrome {

    public static boolean isPalindrome(String str) {
        String modified = "";
        for(int i = 0; i < str.length(); ++i) {
            if(Character.isAlphabetic(str.charAt(i))) {
                modified += Character.toLowerCase(str.charAt(i));
            }
        }
        for(int i = 0; i < modified.length(); ++i) {
            if(modified.charAt(i) != modified.charAt(modified.length()-i-1)) {
                return false;
            }
        }
        return true;
    }

    public static void main(String[] args) {
        if(args.length == 0) {
            System.out.println("Error. command line argument for file name is not provided.");
            System.exit(-1);
        }
        File file = new File(args[0]);
        try {
            Scanner fin = new Scanner(file);
            String line;
            while (fin.hasNextLine()) {
                line = fin.nextLine();
                if(isPalindrome(line)) {
                    System.out.println(line + "\tTrue");
                } else {
                    System.out.println(line + "\tFalse");
                }
            }
            fin.close();
        } catch (FileNotFoundException e) {
            System.out.println(file.getAbsolutePath() + " does not exists!");
        }
    }

}

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