Print calendar for a given year in C++

Prerequisite : Find day of the week for given date

Problem: To print the calendar of any given year. The program should be such that it can prints the calendar of any input year.

Implementation:

// A C++ Program to Implement a Calendar 
// of an year 
#include<bits/stdc++.h> 
using namespace std; 
  
/*A Function that returns the index of the day 
  of the date- day/month/year 
  For e.g- 
  
  Index     Day 
  0         Sunday 
  1         Monday 
  2         Tuesday 
  3         Wednesday 
  4         Thursday 
  5         Friday 
  6         Saturday*/
int dayNumber(int day, int month, int year) 
{ 
  
    static int t[] = { 0, 3, 2, 5, 0, 3, 5, 1, 
                       4, 6, 2, 4 }; 
    year -= month < 3; 
    return ( year + year/4 - year/100 + 
             year/400 + t[month-1] + day) % 7; 
} 
  
/* 
  A Function that returns the name of the month 
  with a given month number 
  
  Month Number     Name 
  0                January 
  1                February 
  2                March 
  3                April 
  4                May 
  5                June 
  6                July 
  7                August 
  8                September 
  9                October 
  10               November 
  11               December */
string getMonthName(int monthNumber) 
{ 
    string months[] = {"January", "February", "March", 
                       "April", "May", "June", 
                       "July", "August", "September", 
                       "October", "November", "December"
                      }; 
  
    return (months[monthNumber]); 
} 
  
/* A Function to return the number of days in 
   a month 
  
  Month Number     Name        Number of Days 
  0                January     31 
  1                February    28 (non-leap) / 29 (leap) 
  2                March       31 
  3                April       30 
  4                May         31 
  5                June        30 
  6                July        31 
  7                August      31 
  8                September   30 
  9                October     31 
  10               November    30 
  11               December    31 
  
*/
int numberOfDays (int monthNumber, int year) 
{ 
    // January 
    if (monthNumber == 0) 
        return (31); 
  
    // February 
    if (monthNumber == 1) 
    { 
        // If the year is leap then February has 
        // 29 days 
        if (year % 400 == 0 || 
                (year % 4 == 0 && year % 100 != 0)) 
            return (29); 
        else
            return (28); 
    } 
  
    // March 
    if (monthNumber == 2) 
        return (31); 
  
    // April 
    if (monthNumber == 3) 
        return (30); 
  
    // May 
    if (monthNumber == 4) 
        return (31); 
  
    // June 
    if (monthNumber == 5) 
        return (30); 
  
    // July 
    if (monthNumber == 6) 
        return (31); 
  
    // August 
    if (monthNumber == 7) 
        return (31); 
  
    // September 
    if (monthNumber == 8) 
        return (30); 
  
    // October 
    if (monthNumber == 9) 
        return (31); 
  
    // November 
    if (monthNumber == 10) 
        return (30); 
  
    // December 
    if (monthNumber == 11) 
        return (31); 
} 
  
// Function to print the calendar of the given year 
void printCalendar(int year) 
{ 
    printf ("         Calendar - %d\n\n", year); 
    int days; 
  
    // Index of the day from 0 to 6 
    int current = dayNumber (1, 1, year); 
  
    // i --> Iterate through all the months 
    // j --> Iterate through all the days of the 
    //       month - i 
    for (int i = 0; i < 12; i++) 
    { 
        days = numberOfDays (i, year); 
  
        // Print the current month name 
        printf("\n  ------------%s-------------\n", 
               getMonthName (i).c_str()); 
  
        // Print the columns 
        printf("  Sun  Mon  Tue  Wed  Thu  Fri  Sat\n"); 
  
        // Print appropriate spaces 
        int k; 
        for (k = 0; k < current; k++) 
            printf("     "); 
  
        for (int j = 1; j <= days; j++) 
        { 
            printf("%5d", j); 
  
            if (++k > 6) 
            { 
                k = 0; 
                printf("\n"); 
            } 
        } 
  
        if (k) 
            printf("\n"); 
  
        current = k; 
    } 
  
    return; 
} 
  
// Driver Program to check above funtions 
int main() 
{ 
    int year = 2016; 
    printCalendar(year); 
  
    return (0); 
} 

Output:

 Calendar - 2016


  ------------January-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                             1    2
    3    4    5    6    7    8    9
   10   11   12   13   14   15   16
   17   18   19   20   21   22   23
   24   25   26   27   28   29   30
   31

  ------------February-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
         1    2    3    4    5    6
    7    8    9   10   11   12   13
   14   15   16   17   18   19   20
   21   22   23   24   25   26   27
   28   29

  ------------March-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
              1    2    3    4    5
    6    7    8    9   10   11   12
   13   14   15   16   17   18   19
   20   21   22   23   24   25   26
   27   28   29   30   31

  ------------April-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                             1    2
    3    4    5    6    7    8    9
   10   11   12   13   14   15   16
   17   18   19   20   21   22   23
   24   25   26   27   28   29   30

  ------------May-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
    1    2    3    4    5    6    7
    8    9   10   11   12   13   14
   15   16   17   18   19   20   21
   22   23   24   25   26   27   28
   29   30   31

  ------------June-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                   1    2    3    4
    5    6    7    8    9   10   11
   12   13   14   15   16   17   18
   19   20   21   22   23   24   25
   26   27   28   29   30

  ------------July-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                             1    2
    3    4    5    6    7    8    9
   10   11   12   13   14   15   16
   17   18   19   20   21   22   23
   24   25   26   27   28   29   30
   31

  ------------August-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
         1    2    3    4    5    6
    7    8    9   10   11   12   13
   14   15   16   17   18   19   20
   21   22   23   24   25   26   27
   28   29   30   31

  ------------September-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                        1    2    3
    4    5    6    7    8    9   10
   11   12   13   14   15   16   17
   18   19   20   21   22   23   24
   25   26   27   28   29   30

  ------------October-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                                  1
    2    3    4    5    6    7    8
    9   10   11   12   13   14   15
   16   17   18   19   20   21   22
   23   24   25   26   27   28   29
   30   31

  ------------November-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
              1    2    3    4    5
    6    7    8    9   10   11   12
   13   14   15   16   17   18   19
   20   21   22   23   24   25   26
   27   28   29   30

  ------------December-------------
  Sun  Mon  Tue  Wed  Thu  Fri  Sat
                        1    2    3
    4    5    6    7    8    9   10
   11   12   13   14   15   16   17
   18   19   20   21   22   23   24
   25   26   27   28   29   30   31

Time Complexity– O(1) . The time taken doesn’t depends on the input year. It is same for any given year.
Auxiliary Space – O(1)

This article is contributed by Rachit Balweriar .If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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