Introduction of Calendar Generator: Display Month-by-Month Calendar for a Given Year in C.
 |
| Display Month-by-Month Calendar for a Given Year in C. |
In this article, we will explore how to create a calendar generator program in the C programming language. The program will allow users to input a specific year, and it will generate a month-by-month calendar for that year.
By following the steps outlined in this article, you will gain a better understanding of how to handle dates, loops, and conditional statements in C programming.
Prerequisites.
Before diving into the implementation, it is assumed that you have a basic understanding of the C programming language, including variables, loops, and conditional statements. Familiarity with functions and arrays will also be helpful.
Implementation Steps.
1. Include Necessary Headers: Begin by including the necessary standard library headers for input/output operations (`stdio.h`) and string manipulation (`string.h`).
2. Create a Function to Determine Leap Years: Since the number of days in February varies based on whether it is a leap year or not, we need to implement a function to check if a given year is a leap year.
Instead of 365 days like in a regular year, a leap year has 366 days. You can use the following logic to determine a leap year:
- If the year is divisible by 4 and not divisible by 100, or
- if the year can be divided by 400.
3. Create a Function to Calculate the Day of the Week: Implement a function that calculates the day of the week for a given date.
You can use Zeller's Congruence algorithm, which takes the year, month, and day as input and returns the corresponding day of the week.
This function will help us determine the starting day for each month in the calendar.
4. Create the Main Function: In the main function, prompt the user to enter the year for which they want to generate the calendar.
Generate the Calendar
Inside the main function, use loops and conditional statements to generate the month-by-month calendar for the given year.
Start by determining the starting day of the year using the day of the week calculation function.
6. Display the Calendar: Print the generated calendar to the console, ensuring the format is clear and readable. Include the month and year at the top of each calendar.
Compile and Run the Program.
Save the code in a C file with the `.c` extension. Use a C compiler to compile the code, and then run the resulting executable.
Output code like this.
#include <stdio.h>
#include <string.h>
// Function to check if a year is a leap year
int isLeapYear(int year) {
if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
return 1;
else
return 0;
}
// Function to calculate the day of the week
int calculateDayOfWeek(int year, int month, int day) {
if (month < 3) {
month += 12;
year--;
}
int century = year / 100;
int yearInCentury = year % 100;
int dayOfWeek = (day + 13 * (month + 1) / 5 + yearInCentury + yearInCentury / 4 + century / 4 + 5 * century) % 7;
return dayOfWeek;
}
// Function to generate the calendar for a given year
void generateCalendar(int year) {
char* months[] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
int daysInMonth[] = {
31, 28 + isLeapYear(year), 31, 30, 31, 30,
31, 31, 30, 31, 30, 31
};
printf("Calendar for the year %d\n", year);
for (int month = 0; month < 12; month++) {
int startingDay = calculateDayOfWeek(year, month + 1, 1);
printf("\n%s\n", months[month]);
printf("Sun Mon Tue Wed Thu Fri Sat\n");
// Print leading spaces
for (int i = 0; i < startingDay; i++) {
printf(" ");
}
// Print days
for (int day = 1; day <= daysInMonth[month]; day++) {
printf("%3d ", day);
if ((day + startingDay) % 7 == 0) {
printf("\n");
}
}
printf("\n");
}
}
int main() {
int year;
printf("Enter the year: ");
scanf("%d", &year);
generateCalendar(year);
return 0;
}
Conclusion.
Congratulations! You have successfully implemented a calendar generator program in C that can display a month-by-month calendar for a given year.
This program demonstrates the use of loops, conditional statements, functions, and arrays to handle dates and generate calendar output.
With further enhancements, you can add features such as user-friendly interfaces, additional formatting options, or even the ability to navigate between different years.
By working on this project, you have gained valuable experience in C programming and improved your skills in handling dates and logical calculations.