DayOfTheWeek.java

public class DayOfTheWeek {

    public static void main(String[] args) {
 
      
 
        //Declaring the variables for year(y), month(m), day(d)
        int y,m,d;
        //Initialisation of the variables y,m and d with the input arguments 
        y = Integer.valueOf(args[0]);
        m = Integer.valueOf(args[1]);
        d = Integer.valueOf(args[2]);
        //Declaring the auxiliary variables used in the formula.
        int y0, m0, d0, x;
  
  
        
        
        // these 4 lines represent the formula for calculating the day of the week
        y0 = y - (14-m)/12;
        x = y0 + (y0)/4 - (y0)/100 + (y0)/400;
        // ((14-m)/12) is bracketed so that the value can be rounded to 0
        m0 = m + (12 * ((14-m)/12)) - 2; 
        d0 = (d + x + 31*(m0)/12)%7;
        
        // below are the conditions of what to print for each value of d0
        if (d0 == 0) {
            System.out.println("SUNDAY");
        } else if (d0 == 1) {
            System.out.println("MONDAY");
        } else if (d0 == 2) {
            System.out.println("TUESDAY");
        } else if (d0 == 3) {
            System.out.println("WEDNESDAY");
        } else if (d0 == 4) {
            System.out.println("THURSDAY");
        } else if (d0 == 5) {
            System.out.println("FRIDAY");
        } else if (d0 == 6) {
            System.out.println("SATURDAY");
        }
        
  
        

    }

}