WeekdayCalculator

Code

import java.util.Scanner;

public class WeekdayCalculator
{
	public static void main( String[] args )
	{
		Scanner keyboard = new Scanner(System.in);

		System.out.println("Welcome to Mr. Davis's fantastic birth-o-meter!");
		System.out.println();
		System.out.println("All you have to do is enter your birth date, and it will");
		System.out.println("tell you the day of the week on which you were born.");
		System.out.println();
		System.out.println("Some automatic tests....");
		System.out.println("12 10 2003 => " + weekday(12,10,2003));
		System.out.println(" 2 13 1976 => " + weekday(2,13,1976));
		System.out.println(" 2 13 1977 => " + weekday(2,13,1977));
		System.out.println(" 7  2 1974 => " + weekday(7,2,1974));
		System.out.println(" 1 15 2003 => " + weekday(1,15,2003));
		System.out.println("10 13 2000 => " + weekday(10,13,2000));
		System.out.println();

		System.out.println("Now it's your turn!  What's your birthday?");
		System.out.print("Birth date (mm dd yyyy): ");
		int mm = keyboard.nextInt();
		int dd = keyboard.nextInt();
		int yyyy = keyboard.nextInt();

		System.out.println("You were born on " + weekday_name(weekday(mm, dd, yyyy)) + ", " + month_name(mm) + " " + dd + ", " + yyyy + ".");
		System.out.println("You were born on ");
	}


    	public static int weekday( int mm, int dd, int yyyy )
        {
        
    		int yy, total;
            String date = "";
            
            yy = yyyy - 1900;
            total = yy / 4;
            total = total + yy;
            total = total + dd;
            total = total + month_offset(mm);
            if (isLeap(yyyy) == true && (mm == 1 || mm == 2))
                total--;
            total = total % 7;
    
    		return total;
    	}
    public static String weekday_name( int weekday )
    {
        String result = "";
        
        if ( weekday == 1 )
        {
            result = "Sunday";
        }
        else if ( weekday == 2 )
        {
            result = " Monday ";
        }
        else if ( weekday == 3 )
        {
            result = " Tuesday ";
        }
        else if ( weekday == 4 )
        {
            result= " Wednesday";
        }
        else if ( weekday == 5 )
        {
            result = " Thursday";
        }
        else if ( weekday == 6 )
        {
            result = " Friday ";
        }
        else if ( weekday == 7 );
        {
            result = "Saturday";
        }
        
        return result;
    }
    
    public static String month_name( int n )
    {
        String monthName="";
        
        if (n == 1)
        {
            monthName = " Jan ";
        }
        else if (n == 2)
        {
            monthName = " Feb ";
        }
        else if ( n == 3)
        {
            monthName = " Mar ";
        }
        else if ( n == 4 )
        {
            monthName = " Apr ";
        }
        else if ( n == 5 )
        {
            monthName = " May ";
        }
        else if ( n == 6 )
        {
            monthName = " June ";
        }
        else if ( n == 7 )
        {
            monthName = "Jul";
        }
        else if ( n == 8 )
        {
            monthName = " Aug ";
        }
        else if ( n == 9 )
        {
            monthName = "Sept";
        }
        else if ( n == 10 )
        {
            monthName = "Oct";
        }
        else if ( n == 11 )
        {
            monthName = "Nov";
        }
        else if ( n == 12 )
        {
            monthName = "Dec";
        }
        
        return monthName;
    }
    public static int month_offset(int n )
    {
        int monthOffset=0;
        
        if ( n == 1 )
        {
            monthOffset = 1;
        }
        else if ( n == 2 )
        {
            monthOffset = 2;
        }
        else if ( n == 3 )
        {
            monthOffset = 3;
        }
        else if ( n == 4 )
        {
            monthOffset = 4;
        }
        else if ( n == 5 )
        {
            monthOffset = 5;
        }
        else if ( n == 6 )
        {
            monthOffset = 6;
        }
        else if ( n == 7 )
        {
            monthOffset = 7;
        }
        else if ( n == 8 )
        {
            monthOffset = 8;
        }
        else if ( n == 9 )
        {
            monthOffset = 9;
        }
        else if ( n == 10 )
        {
            monthOffset = 10;
        }
        else if ( n == 11 )
        {
            monthOffset = 11;
        }
        else if ( n == 12 )
        {
            monthOffset = 12;
        }
        return monthOffset;
    }


	// paste your methods from MonthName, WeekdayName, and MonthOffset here
		
	public static boolean isLeap( int year )
	{
		// years which are evenly divisible by 4 are leap years,
		// but years divisible by 100 are not leap years,
		// though years divisible by 400 are leap years
		boolean result;

		if ( year%400 == 0 )
			result = true;
		else if ( year%100 == 0 )
			result = false;
		else if ( year%4 == 0 )
			result = true;
		else
			result = false;
		
		return result;
	}
}

WeekdayCalculator