/* 1.Leap if a it's a multiple of 4，eg：1996、2012、2016
   2.Do not leap if it's a multiple of 100，eg：1800、1900、2100
   3.Leap if a it's a multiple of 400，eg：1600、2000、2400
   4.Do not leap if it's a multiple of 4000，eg：4000、8000 */

#include <stdio.h>
#include <stdlib.h>

enum monthnumber
{
	Jan = 1, Feb, Mar, April, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec
}

enum monthdays
{
	Jan = 31, FebUsual = 28, FebLeap = 29, Mar = 31, April = 30, May = 31, Jun = 30, Jul = 31, Aug = 31,
	Sep = 30, Oct = 31, Nov = 30, Dec = 31
}

int JanFirstWeekDay(int year) // jan 1st of the assign year
{
	// 1900 happens to be a multiple of 4 and 100 (No Leap) , Jan 1st of 1900 is monday , so i start from 1900
	// 365/7=52...1
	cycle = (year - 1900) / 4;
	single = (year - 1900) % 4;

	// every cycle (four years) passed , the week day of Jan 1st postponed by 5 days
	// every single (one year) passed , the week day of Jan 1st postponed by 1 days
	return (cycle * 5 + single);
}


int dayPassed(int year , int month) // day passed in assigned year until the assigned month
{
	enum monthnumber month;

	single = (year - 1900) % 4;
	if (single == 0)
		FEB = 29;
	else
		FEB = 28;


	days
}

int main()
{
	struct months calendar;
	int year = 0;
	int month = 0;
	int janFirstDay; // Jan 1st of the assign year
	int day; // day passed in the assigned month

	printf("which year? ( Between 1901 and 2099 ) \n");
	scanf("%d", &year);
	printf("which month? \n");
	scanf("%d", &month);

	janFirstDay = JanFirstWeekDay(year);


	int JAN = 31, FEB = 29, MAR = 31, APR = 30, MAY = 31, JUN = 30, JUL = 31, AUG = 31, SEP = 30, OCT = 31, NOV = 30, DEC = 31;

	if (single == 0)
	{
		FEB = 29;
	}

	else
	{
		FEB = 28;
	}



	int day; // day passed in the assigned month

	if (month == 1)
		day = 0;
	if (month >= 2)
		day = JAN;
	if (month >= 3)
		day = day + FEB;
	if (month >= 4)
		day = day + MAR;
	if (month >= 5)
		day = day + APR;
	if (month >= 6)
		day = day + MAY;
	if (month >= 7)
		day = day + JUN;
	if (month >= 8)
		day = day + JUL;
	if (month >= 9)
		day = day + AUG;
	if (month >= 10)
		day = day + SEP;
	if (month >= 11)
		day = day + OCT;
	if (month >= 12)
		day = day + NOV;

	/*
	int totalday, weekday;

	totalday = janoneday + day;
	weekday = (totalday % 7) + 1; // 1900 jan 1st Monday

	// if weekday=1 , the first day of the assign month is Monday
	// if weekday=7 , the first day of the assign month is Sunday

	printf("_____________________________\n\n");
	printf("       %d    ", year);

	if (month == 1)
		printf("January\n");
	if (month == 2)
		printf("Febuary\n");
	if (month == 3)
		printf("March\n");
	if (month == 4)
		printf("April\n");
	if (month == 5)
		printf("May\n");
	if (month == 6)
		printf("June\n");
	if (month == 7)
		printf("July\n");
	if (month == 8)
		printf("August\n");
	if (month == 9)
		printf("Septenber\n");
	if (month == 10)
		printf("October\n");
	if (month == 11)
		printf("Novenber\n");
	if (month == 12)
		printf("December\n");

	printf("_____________________________\n");
	printf(" SUN MON TUE WED THU FRI SAT\n");

	int i = 1, calentotal;

	weekday = weekday + 1; // because on the calender Sunday is first day

	// now weekday doesn't stands for "what day is the day" but stands for which colume is the day

	if (weekday == 8)
	{
		weekday = 1;
	}

	printf("  ");

	// Start Printing

	while (i < weekday)
	{
		printf("    ");
		i = i + 1;
	}

	// the first week

	while (i >= weekday && i <= 7)
	{
		printf(" %d  ", (i - weekday + 1));
		i = i + 1;
	}

	printf("\n");
	printf("  ");

	// the second week

	while (i > 7 && i < weekday + 9)
	{
		printf(" %d  ", (i - weekday + 1));

		if ((i % 7) == 0)
		{
			printf("\n");
			printf("  ");
		}
		i = i + 1;
	}

	// days after 10th

	int monthday; // how many days for the assigned month

	if (month == 1)
		monthday = JAN;
	if (month == 2)
		monthday = FEB;
	if (month == 3)
		monthday = MAR;
	if (month == 4)
		monthday = APR;
	if (month == 5)
		monthday = MAY;
	if (month == 6)
		monthday = JUN;
	if (month == 7)
		monthday = JUL;
	if (month == 8)
		monthday = AUG;
	if (month == 9)
		monthday = SEP;
	if (month == 10)
		monthday = OCT;
	if (month == 11)
		monthday = NOV;
	if (month == 12)
		monthday = DEC;

	calentotal = weekday + monthday;

	while (i < calentotal)
	{
		printf("%d  ", (i - weekday + 1));

		if ((i % 7) == 0)
		{
			printf("\n");
			printf("  ");
		}

		i = i + 1;
	}

	printf("\n");
	printf("_____________________________\n\n");
	*/
	return 0;
}