January 18, 2016

In java there is a Calendar class which we use to print the date. In this tutorial I’m going to show you how to print a Calendar without using the predefined class.


package technoblog.post;
import java.util.Scanner;

public class PrintCalendar {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		System.out.println("         Calender       ");
		System.out.println("");
		System.out.println(":Bye Techno Blogger");
		System.out.println("");
		System.out.println("");
		System.out.print("Enter full year (YYYY): ");
		int year = scan.nextInt();

		System.out.print("Enter month in number between 1 and 12(MM): ");
		int month = scan.nextInt();

		if (month < 1 || month > 12 || year < 1980)
			System.out.println("Wrong input!");
		else
			printMonth(year, month);
	}

	static void printMonth(int year, int month) {
		printMonthTitle(year, month);
		printMonthBody(year, month);
	}

	static void printMonthTitle(int year, int month) {
		System.out.println("         " + getMonthName(month) + " " + year);
		System.out.println(" ");
		System.out.println(" Sun Mon Tue Wed Thu Fri Sat");
	}

	static String getMonthName(int month) {
		String monthName = null;
		switch (month) {
		case 1:
			monthName = "January";
			break;
		case 2:
			monthName = "February";
			break;
		case 3:
			monthName = "March";
			break;
		case 4:
			monthName = "April";
			break;
		case 5:
			monthName = "May";
			break;
		case 6:
			monthName = "June";
			break;
		case 7:
			monthName = "July";
			break;
		case 8:
			monthName = "August";
			break;
		case 9:
			monthName = "September";
			break;
		case 10:
			monthName = "October";
			break;
		case 11:
			monthName = "November";
			break;
		case 12:
			monthName = "December";
		}
		return monthName;
	}

	static void printMonthBody(int year, int month) {
		int startDay = getStartDay(year, month);
		int numberOfDaysInMonth = getNumberOfDaysInMonth(year, month);

		int i = 0;
		for (i = 0; i < startDay; i++)
			System.out.print("    ");
		for (i = 1; i <= numberOfDaysInMonth; i++) {
			if (i < 10)
				System.out.print("   " + i);
			else
				System.out.print("  " + i);
			if ((i + startDay) % 7 == 0)
				System.out.println();
		}
		System.out.println();
	}

	static int getStartDay(int year, int month) {
		int startDay1800 = 3;
		int totalNumberOfDays = getTotalNumberOfDays(year, month);
		return (totalNumberOfDays + startDay1800) % 7;
	}

	static int getTotalNumberOfDays(int year, int month) {
		int total = 0;

		// Get the total days from 1800 to year - 1
		for (int i = 1800; i < year; i++)
			if (isLeapYear(i))
				total = total + 366;
			else
				total = total + 365;

		// Add days from January to the month prior to the calendar month
		for (int i = 1; i < month; i++)
			total = total + getNumberOfDaysInMonth(year, i);

		return total;
	}

	/** Get the number of days in a month */

	static int getNumberOfDaysInMonth(int year, int month) {
		if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8
				|| month == 10 || month == 12)
			return 31;

		if (month == 4 || month == 6 || month == 9 || month == 11)
			return 30;

		if (month == 2)
			return isLeapYear(year) ? 29 : 28;

		return 0; // If month is incorrect
	}

	/** Determine if it is a leap year */
	static boolean isLeapYear(int year) {
		return year % 400 == 0 || (year % 4 == 0 && year % 100 != 0);
	}
} 

Try on this code guys, you will love it.
Happy Coding !!!