PROBLEM 21:

Mr. Bhola is fed-up of giving individual dates as inputs. He wants a complete calendar starting from 1st January to 31st December for a given year.

Write a C program that takes input as a int in format yyyy.

CODE:

#include<stdio.h>

#define TRUE 1

#define FALSE 0

int days_in_month[]={0,31,28,31,30,31,30,31,31,30,31,30,31};

char *months[]=

{

    " ",

    "\n\n\nJanuary",

    "\n\n\nFebruary",

    "\n\n\nMarch",

    "\n\n\nApril",

    "\n\n\nMay",

    "\n\n\nJune",

    "\n\n\nJuly",

    "\n\n\nAugust",

    "\n\n\nSeptember",

    "\n\n\nOctober",

    "\n\n\nNovember",

    "\n\n\nDecember",

};

    int inputyear()

    {

        int year;

        printf("Enter any year:\n");

        scanf("%d",&year);

        return year;

    }

    int determinedaycode(int year)

    {

        int daycode;

        int d1,d2,d3;

        d1=(year-1.)/4.0;

        d2=(year-1.)/100.;

        d3=(year-1.)/400.;

        daycode = (year + d1-d2+d3)%7;

        return daycode;

    }

    int determineleapyear(int year)

    {

        if(year%4==FALSE && year%100!=FALSE|| year%100==FALSE)

        {

            days_in_month[2]=29;

            return TRUE;

        }

        else

        {

            days_in_month[2]=28;

            return FALSE;

        }

    }

    void calender(int year,int daycode)

    {

        int month,day;

        for(month=1;month<=12;month++)

        {

            printf("%c",months[month]);

            printf("\n\nSun  Mon  Tues  Wed  Thurs  Fri  Sat\n");

            for(day=1;day<=1+daycode * 5;day++)

            {

                printf(" ");

            }

            for(day=1;day<=days_in_month[month];day++)

            {

                printf("%2d",day);

                if((day + daycode)%7>0)

                printf("  " );

                else

                printf("\n " );

            }

            daycode=(daycode+daycode+days_in_month[month])%7;

        }

    }

    int main()

    {

        int year,daycode,leapyear;

        year=inputyear();

        daycode=determinedaycode(year);

        determineleapyear(year);

        calender(year,daycode);

        printf("\n");

return 0;

    }

Program Output:

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