Here a code
prints a calendar for a year specified. The user enters a year for the calendar
and the program prints the calendar in text format. The days are define by
integer like (0 = Sun, 1 = Mon,... etc.) and Leap year is defined by 1 and 0
like (0 = no leap year, 1 = leap year).
Source code:
#define _CRT_SECURE_NO_WARNINGS
#define TRUE 1
#define FALSE 0
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
int get_year(void)
{
int year
= -1;
printf("Type a year : ");
scanf("%d", &year);
if (year
== -1)
{
time_t rawtime;
struct tm *
timeinfo;
time(&rawtime);
timeinfo = localtime(&rawtime);
year = timeinfo->tm_year + 1900;
}
return year;
}
int get_day_code(int year)
{
int day_code;
int x1,
x2, x3;
x1 = (year - 1.) / 4.0;
x2 = (year - 1.) / 100.;
x3 = (year - 1.) / 400.;
day_code = (year + x1 - x2 + x3) % 7;
return day_code;
}
/*
simple algorithm to know a year is leap
or not can be defined as follows
if (year is not divisible by 4) then(it
is a common year)
else if (year is not divisible by 100)
then(it is a leap year)
else if (year is not divisible by 400)
then(it is a common year)
else (it is a leap year)
*/
int get_leap_year(int year)
{
if (((year % 4
== 0) && (year % 100 != 0)) || (year %
400 == 0))
return TRUE;
else
return FALSE;
}
void print_calendar(int year, int day_code, int leap_year) //function
header
{
int days_in_month; /* number of
days in month currently being printed */
int day;
/* counter for day of month */
int month; /* month = 1
is Jan, month = 2 is Feb, etc. */
printf("\t\t\t\t%d", year);
for (month
= 1; month <= 12; month++)
{
switch (month)
{
/* print
name and set days_in_month */
case 1:
printf("\n\nJanuary");
days_in_month = 31;
break;
case 2:
printf("\n\nFebruary");
days_in_month = leap_year ? 29
: 28;
break;
case 3:
printf("\n\nMarch");
days_in_month = 31;
break;
case 4:
printf("\n\nApril");
days_in_month = 30;
break;
case 5:
printf("\n\nMay");
days_in_month = 31;
break;
case 6:
printf("\n\nJune");
days_in_month = 30;
break;
case 7:
printf("\n\nJuly");
days_in_month = 31;
break;
case 8:
printf("\n\nAugust");
days_in_month = 31;
break;
case 9:
printf("\n\nSeptember");
days_in_month = 30;
break;
case 10:
printf("\n\nOctober");
days_in_month = 31;
break;
case 11:
printf("\n\nNovember");
days_in_month = 30;
break;
case 12:
printf("\n\nDecember");
days_in_month = 31;
break;
}
printf("\n\nSun\tMon\tTue\tWed\tThu\tFri\tSat\n");
/* advance
printer to correct position for first date */
for (day
= 1; day < day_code + 1;
day++)
printf("\t");
/* print the
dates for one month */
for (day
= 1; day <= days_in_month; day++)
{
printf("%2d", day);
if ((day
+ day_code) % 7 > 0) /* before
Sat? */
/* move to
next day in same week */
printf("\t");
else if (day
!= days_in_month)
/* skip to next line to start with Sun
*/
printf("\n");
}
/* set
day_code for next month to begin */
day_code = (day_code +
days_in_month) % 7;
}
}
int main()
{
int year,
day_code, leap_year;
year = get_year();
day_code = get_day_code(year);
leap_year = get_leap_year(year);
print_calendar(year, day_code, leap_year);
_getch();
return 0;
}
Output:
