Assignemnt #96: Weekday Calculator

Code

    /// Name: Cassie
    /// Period: 6
    /// Program Name: Weekday Calculator
    /// File Name: Weekday.java
    /// Date Finished: 3/4/2016
    
    import java.util.Scanner;
    
    public class Weekday
    {
    	public static void main( String[] args )
    	{
    		Scanner keyboard = new Scanner(System.in);
    
    		System.out.println("Welcome to Rachel'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 => " + weekdays(12,10,2003));
    		System.out.println(" 2 13 1976 => " + weekdays(2,13,1976));
    		System.out.println(" 2 13 1977 => " + weekdays(2,13,1977));
    		System.out.println(" 7  2 1974 => " + weekdays(7,2,1974));
    		System.out.println(" 1 15 2003 => " + weekdays(1,15,2003));
    		System.out.println("10 13 2000 => " + weekdays(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 " + weekdays(mm, dd, yyyy) );
        }
        
        public static String month_name( int month )
        {
            String result = "error";
    
            if ( month == 1 ) {
                result = "January";
            }
    
            else if ( month == 2 ) {
                result = "February";
            }
    
            else if ( month == 3 ) {
                result = "March";
            }
    
            else if ( month == 4 ) {
                result = "April";
            }
    
            else if ( month == 5 ) {
                result = "May";
            }
    
            else if ( month == 6 ) {
                result = "June";
            }
    
            else if ( month == 7 ) {
                result = "July";
            }
    
            else if ( month == 8 ) {
                result = "August";
            }
    
            else if ( month == 9 ) {
                result = "September";
            }
    
            else if ( month == 10 ) {
                result = "October";
            }
    
            else if ( month == 11 ) {
                result = "November";
            }
    
            else if ( month == 12 ) {
                result = "December";
            }
    
    
    
            return result;
        }
        
        public static int monthOffset( int month )
        {
            int result = 1;
    
            if ( month == 1 || month == 10 ) {
                result = 1;
            }
    
            else if ( month == 2 || month == 3 || month == 11 ) {
                result = 4;
            }
    
            else if ( month == 4 || month == 7 ) {
                result = 0;
            }
    
            else if ( month == 9 || month == 12 ) {
                result = 6;
            }
    
            else if ( month == 5 ) {
                result = 2;
            }
    
            else if ( month == 6 ) {
                result = 5;
            }
    
            else if ( month == 8 ) {
                result = 3;
            }
    
            return result;
        }
    		
    	public static boolean isLeap( int yyyy )
    	{
    		// 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 ( yyyy%400 == 0 )
    			result = true;
    		else if ( yyyy%100 == 0 )
    			result = false;
    		else if ( yyyy%4 == 0 )
    			result = true;
    		else
    			result = false;
    		
    		return result;
    	}
        
        public static String weekday_name(int yyyy, int mm, int dd)   
        {
            		int yy, total, day;
    		String date = "";
                yy = yyyy - 1900;
            total = yy/ 4 + yy + monthOffset(mm) + dd;
            
            if ( isLeap(yyyy) == true && mm == 1 )
                total = total - 1;
            
            else if ( isLeap(yyyy) == true && mm ==2 )
                    total = total -1 ;
            
    		// bunch of calculations go here
            
            String Day;
            day = total % 7;
            
            if ( day == 1 )
                Day = "Sunday";
            else if ( day == 2 )
                Day = "Monday";
            else if ( day == 3 )
                Day = "Tuesday";
            else if ( day == 4 )
                Day = "Wednesday";
            else if ( day == 5 )
                Day = "Thursday";
            else if ( day == 6 )
                Day = "Friday";
            else if ( day == 7 )
                Day = "Saturday";
            else
                Day = "error";
            
            
            return Day;
        }
        
        public static String weekdays( int mm, int dd, int yyyy )
    	{
    		int yy, total, day;
    		String date = "";
            yy = yyyy - 1900;
            total = yy / 4 + yy + monthOffset(mm) + dd;
            
            if ( isLeap(yyyy) == true && mm == 1 ) {
                total = total - 1;
            }
            
            else if ( isLeap(yyyy) == true && mm == 2 ) {
                total = total - 1;
            }
            
            day = total % 7;
    
    		date = weekday_name(yyyy,mm,dd) + ", " + mm + " " + dd + ", " + yyyy;
    
    		return date;
    	}
    }


    

Picture of the output