Calendar

// C program to print the month by month  //
// calendar for the given year //

#include <stdio.h>

// Function that returns the index of the //
// day for date DD/MM/YYYY //
int dayNumber(int day, int month, int year)
{

	static int t[] = { 0, 3, 2, 5, 0, 3,
					5, 1, 4, 6, 2, 4 };
	year -= month < 3;
	return (year + year / 4
			- year / 100
			+ year / 400
			+ t[month - 1] + day)
		% 7;
}

// Function that returns the name of the //
// month for the given month Number //
// January - 0, February - 1 and so on //
char* getMonthName(int monthNumber)
{
	char* month;

	switch (monthNumber) {
	case 0:
		month = "January";
		break;
	case 1:
		month = "February";
		break;
	case 2:
		month = "March";
		break;
	case 3:
		month = "April";
		break;
	case 4:
		month = "May";
		break;
	case 5:
		month = "June";
		break;
	case 6:
		month = "July";
		break;
	case 7:
		month = "August";
		break;
	case 8:
		month = "September";
		break;
	case 9:
		month = "October";
		break;
	case 10:
		month = "November";
		break;
	case 11:
		month = "December";
		break;
	}
	return month;
}

// Function to return the number of days //
// in a month //
int numberOfDays(int monthNumber, int year)
{
	// January //
	if (monthNumber == 0)
		return (31);

	// February //
	if (monthNumber == 1) {
		// If the year is leap then Feb //
		// has 29 days //
		if (year % 400 == 0
			|| (year % 4 == 0
				&& year % 100 != 0))
			return (29);
		else
			return (28);
	}

	// March //
	if (monthNumber == 2)
		return (31);

	// April //
	if (monthNumber == 3)
		return (30);

	// May //
	if (monthNumber == 4)
		return (31);

	// June //
	if (monthNumber == 5)
		return (30);

	// July //
	if (monthNumber == 6)
		return (31);

	// August //
	if (monthNumber == 7)
		return (31);

	// September //
	if (monthNumber == 8)
		return (30);

	// October //
	if (monthNumber == 9)
		return (31);

	// November //
	if (monthNumber == 10)
		return (30);

	// December //
	if (monthNumber == 11)
		return (31);
}

// Function to print the calendar of //
// the given year //
void printCalendar(int year)
{
	printf("	 Calendar - %d\n\n", year);
	int days;

	// Index of the day from 0 to 6 //
	int current = dayNumber(1, 1, year);

	// i for Iterate through   months //
	// j for Iterate through days //
	// of the month - i //
	for (int i = 0; i < 12; i++) {
		days = numberOfDays(i, year);

		// Print the current month name//
		printf("\n ------------%s-------------\n",
			getMonthName(i));

		// Print the columns//
		printf(" Sun Mon Tue Wed Thu Fri Sat\n");

		// Print appropriate spaces//
		int k;
		for (k = 0; k < current; k++)
			printf("	 ");

		for (int j = 1; j <= days; j++) {
			printf("%5d", j);

			if (++k > 6) {
				k = 0;
				printf("\n");
			}
		}

		if (k)
			printf("\n");

		current = k;
	}

	return;
}


int main()
{
	int year;
    printf("enter the year :\n ");
    scanf("%d",&year);

	printCalendar(year);
	return 0;
}