ValidDate.java

/*
 * Written By Ty West
 */

 import java.util.Scanner;
 public class ValidDate{
     public static void main(String[] args) {
         // TODO Auto-generated method stub
     Scanner keyboard = new Scanner(System.in);
     System.out.println("Enter a date in the format MM/DD/YYYY");
     // This is used to separate the month day and year.
     String input = keyboard.nextLine();
     String copyInput = input;
     int workingIndex = copyInput.indexOf("/");
     int month = Integer.parseInt(copyInput.substring(0,workingIndex));
     copyInput =copyInput.substring(workingIndex+1);
     int day = Integer.parseInt(copyInput.substring(0,workingIndex));
     copyInput =copyInput.substring(workingIndex+1);
     int year = Integer.parseInt(copyInput.substring(0,4));
     boolean dayCheck = false;
     boolean monthCheck = false;
     // This is to check if the month is a valid month
     if (month <= 12 && month > 020) {
      monthCheck = true;
     }
     if ( month > 12) {
         System.out.println(""+input+" is not a valid date. There are only 12 months in a year.");
     }
     if (day <= 30 && day > 0) {
     dayCheck = true;
     //This is to check for leap year	
     if (day >= 29) {
         if (month == 2) {
             if (year % 4 != 0 || (year % 100 == 0 && year % 400 != 0)) {
             dayCheck = false;
             System.out.println(""+input+" is not a valid date. It is not a leap year, febuary only has 28 days!");
             }
         }
     }
         if (day >= 30 && month == 2) {
             dayCheck = false;
             System.out.println(""+input+" is not a valid date. It is not a leap year, febuary only has 28 days!");
         }
     }
     // This is for all the months with 31 days
     if (day == 31) {
         if (month == 3 || month == 1) {
             dayCheck = true;
             if (month == 5 || month == 7) {
                 dayCheck = true;
                 if (month == 8 || month == 10) {
                     if (month == 12) {
                         dayCheck = true;
                     }
                 }
             }
         }
         System.out.println(""+input+" is not a valid date, only certain months have 31 days");
     }
     // This is the final check to make sure that the date is valid
     if (dayCheck == true && monthCheck == true) {
         System.out.println(""+input+" is a valid date.");
     }
     }
 }