Question

A date written in MMDDYYYY format is palindromic if it is read identically from left to right and from right to left. For example, the date February 2, 2020 (02022020).

Develop a Java program (called Palindrome Dates.java) that identifies all palindromic dates in a given year. The program must have the following functionality:

When running the program, the user is prompted to enter a year A.
Afterwards, the program calculates all the palindromic dates and prints them on the screen (separated by a space) in MMDDYYYY format.
Finally, the program prints on the screen the total number of palindromic dates in that year.
Tip: use the LocalDate and DateTimeFormatter classes included in Java to handle dates. For this, it requires doing two imports:
import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
To iterate between dates you can use the following example which increments the start date by one day until it arrives just before the end date.
for (LocalDate date = start; date.isBefore (end); date = date.plusDays (1)) {
         // Processing of the date contained in the date object
}

Answer 1

Hi,

Please find below given code as per your requirement.

Let me know if you have any concern/doubt in this answer via comments.

Hope this answer helps you.

Thanks.

/********************JAVA CODE***********************/

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.util.Scanner;

public class PalindromeDates {

        //Date format
        static DateTimeFormatter customFormatter = DateTimeFormatter.ofPattern("MMddyyyy");
         
        public static void main(String[] args) {
                //Scanner class is used to take user input from console
                Scanner sc = new Scanner(System.in);
                //prompting user to enter year
                System.out.print("Please enter year : ");
                //storing year in variable
                int year = Integer.valueOf(sc.nextLine());
                //calling method which identifies palindroms in given year
                identifyPalindromicDates(year);
        }

        /**
         * This method takes year as parameter and prints all palindrom dates present in that year.
         * @param year
         */
        public static void identifyPalindromicDates(int year) {
                //setting year in local date with first day of year
                LocalDate start = LocalDate.of(year, 1,1);
                //setting end date to next year to set boundary
                LocalDate end = LocalDate.of(year+1, 1, 1);
                int totalPanlindromeDates = 0;
                for (LocalDate date = start; date.isBefore(end); date = date.plusDays (1)) {
                        //formatting date in string 
                        String formattedDate = customFormatter.format(date);
                        //reversed the formatted string
                        String reverseDate = reverseString(formattedDate);
                        //if formatted and reversed string is same  then it is palindrom
                        if(formattedDate.equals(reverseDate)) {
                                System.out.print(formattedDate + " ");
                                totalPanlindromeDates++;
                        }
                }
                System.out.println("\nTotal Palindrom in "+year+ " is : "+totalPanlindromeDates);

        }
        
        /**
         * Reverse the given string in parameter and returns
         * @param inputString
         * @return
         */
        public static String reverseString(String inputString) {
                
                char[] strCharArray = new char[inputString.length()];
                int counter = 0;
                for (int i = inputString.length() - 1; i >= 0; i--) {
                        strCharArray[counter] = inputString.charAt(i);
                        counter++;
                }
                return String.valueOf(strCharArray);
        }

}