#include <stdio.h>
#include <conio.h>

typedef struct calender
{
	int month[6][7];
}cal;

cal obj[12];// CONTAINS ALL THE 12 MONTHS

int i;   	//
int j;   	// LOOP CONTROL VARIABLES
int k;   	//
int gfl; 	// GLOBAL FLAG VARIABLES

int month_value[] =	{
						31,28,31,30,
						31,30,31,31,
						30,31,30,31
					};

char month_name[][10] = {
							"January",	"February",	"March",	"April",
							"May",		"June",		"July",		"August",
							"September","October",	"November",	"December"
						};

void create_calendar(int, int);
void print_calendar(int ,int, int);
void leap_check(int);

int main()
{
	int year;
	int day_number;
	int option;
	int month_no;

	do
	{
		clrscr();
		printf("\n\t\t====================");
		printf("\n\t\t      CALENDAR");
		printf("\n\t\t====================");
		printf("\n\n\tDefine The Year .............. [1]");
		printf("\n\n\tView A Particular Month ...... [2]");
		printf("\n\n\tView The Whole Year .......... [3]");
		printf("\n\n\tExit ......................... [0]");
		printf("\n\n\tEnter Option : ");
		scanf("%d",&option);
		switch(option)
		{
			case 1 :
				clrscr();
				gfl = 1;
				printf("\n\n\tEnter The Year : ");
				scanf("%d", &year);
				printf("\n\n\tEnter The Day Number Of 1st January : ");
				scanf("%d", &day_number);
				create_calendar(year,day_number);
				break;
			case 2 :
				clrscr();
				if(gfl == 0)
				{
					printf("\n\n\tYear Not Defined!");
					printf("\n\n\tPress Enter To Continue ... ");
					fflush(stdin);
					getchar();
					break;
				}
				printf("\n\n\tEnter The Month Number That You Would Like To See : ");
				scanf("%d", &month_no);
				print_calendar(month_no - 1,month_no,year);
				break;
			case 3 :
				clrscr();
				if(gfl == 0)
				{
					printf("\n\n\tYear Not Defined!");
					printf("\n\n\tPress Enter To Continue ... ");
					fflush(stdin);
					getchar();
					break;
				}
				print_calendar(0,12,year);
				break;
			case 0 :
				printf("\n\n\tThank You ... ");
				break;
			default :
				printf("\n\n\tWrong Choice!");
				printf("\n\n\tPress Enter To Continue ... ");
				fflush(stdin);
				getchar();
				break;
		}
	}while(option != 0);

	return 0;
}

void leap_check(int year)
{
	if(year%400 == 0)
		month_value[1] = 29;
	else
	{
		if(year%100 != 0 && year%4 == 0)
			month_value[1] = 29;
	}
}

void create_calendar(int year,int day_number)
{
	int count;
	int fl;
	int limit;

	leap_check(year);
	limit = day_number-1;
	count = 1;
	fl = 0;

	for(i = 0;i < 12;i++)				// TRAVERSING THROUGH MONTHS
	{
		for(j = 0;j < 6;j++)			// TRAVERSING THROUGH WEEKS
		{
			if(j != 0)
				limit = 0;

			for(k = limit;k < 7;k++)	// TRAVERSING THROUGH DAYS
			{
				if(count <= month_value[i])
				{
					obj[i].month[j][k] = count;
					count++;
				}
				else					// END OF A MONTH
				{
					limit = k;
					count = 1;
					fl = 1;
				}
				if(fl == 1)
					break;
			}
			if(fl == 1)
				break;
		}
		fl = 0;
	}
}

void print_calendar(int lower,int upper,int year)
{
	clrscr();
	printf("\n\t\t. : YEAR %d : .\n\n", year);

	for(i = lower;i < upper;i++)
	{
		printf("\t%s\n\n",month_name[i]);
		printf("\tSUN\tMON\tTUE\tWED\tTHU\tFRI\tSAT\n");

		for(j = 0;j < 6;j++)
		{
			for(k = 0;k < 7;k++)
			{
				if(obj[i].month[j][k] != 0)
					printf("\t%d",obj[i].month[j][k]);
				else
					printf("\t");
			}
			printf("\n");
		}
		printf("\n");
	}

	printf("\n\n\tPress Enter To Continue ... ");
	fflush(stdin);
	getchar();
}