Calendar성훈이코드

#include <stdio.h>

void printCalender(int year, int first);
void printFirstTab(int month, int year);
int printDays(int month, int year, int leftDays);
void print_space();
void print_days(int day);
int daysOfMonth(int month, int year);
int IsLeafYear(int year);

void printCalender(int year, int first)
{
	int month, leftDays;

	for(month = 1 ; month <= 12 ; month++)
	{
		printFirstTab(month, year);
		leftDays = printDays(month, year, first);
		first = leftDays;
	}
}

void printFirstTab(int month, int year)
{
	switch(month)
	{
		case 1:
			printf("		January		%d	   \n", year);
			break;
		case 2:
			printf("		February	%d	   \n", year);
			break;
		case 3:
			printf("		March		%d	   \n", year);
			break;
		case 4:
			printf("		April		%d	   \n", year);
			break;
		case 5:
			printf("		May			%d	   \n", year);
			break;
		case 6:
			printf("		June		%d	   \n", year);
			break;
		case 7:
			printf("		July		%d	   \n", year);
			break;
		case 8:
			printf("		August		%d	   \n", year);
			break;
		case 9:
			printf("		September	%d	   \n", year);
			break;
		case 10:
			printf("		October		%d	   \n", year);
			break;
		case 11:
			printf("		November	%d	   \n", year);
			break;
		case 12:
			printf("		December	%d	   \n", year);
			break;
	}
	printf("---------------------------------------------------\n");
	printf("Mon	Tue	Wed	Thu	Fri	Sat	Sun\n");
}

int printDays(int month, int year, int leftDays)
{
	int cnt = 0;
	int day = daysOfMonth(month, year);

	for(int i = 1 ; i <= leftDays ; i++)
	{
		print_space(); //print space leftDays times
		cnt++;
	}

	for(int nowday = 1 ; nowday <= day ; nowday++) //print day from 1 to day
	{
		if(cnt == 7){
			printf("\n");
			cnt = 0;
		}

		print_days(nowday);
		cnt++;
	}
	
	printf("\n\n");
	return cnt;
}

void print_space()
{
	printf("\t");
}

void print_days(int day)
{
	printf("%d\t", day);
}

int daysOfMonth(int month, int year)
{
	int days;

	switch(month)
	{
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12:
			days = 31;
			break;
		
		case 4:
		case 6:
		case 9:
		case 11:
			days = 30;
			break;

		case 2:
			if(IsLeafYear(year) == 0) days = 29;
			else	days = 28;
			break;
	}

	return days;
}

int IsLeafYear(int year)
{
	if(year%4 == 0)	
		return 0; //True

		if(year%100 == 0)
			return 1; //False

			if(year%400 == 0)
				return 0; //True
	else
		return 1; //False
}