C Prayer Times

Islamic prayer time calculator source for any projects written in the C/C++ programming language

ممصدر حاسبة مواقيت الصلاة الإسلامية لأي مشاريع مكتوبة بلغة البرمجة C، أو C++

Based on: https://radhifadlillah.com/blog/2020-09-06-calculating-prayer-times/

How to use

You can use this source for both Windows and Linux, MacOS is untested. To use it, you need to copy the files athan_calculator.c and athan_calculator.h to your project. In your project, you will need to get your current georgian date, there is a structure built into athan_calculator.h that the function calculate_prayer_times utilizes.

struct georgian_date {
  int day;
  int month;
  int year;
};

There are multiple parameters you need to account for in the calculation:

1. Latitude
2. Longitude
3. Elevation
4. Time zone
5. Asr shadow factor
6. Fajr sun angle
7. Isha sun angle

Parameter explanations

Longitude and Latitude

This should be the approximate location of where you live. If you want, you can set it to exactly where you live, but for security reasons you should only set it to the city you live in.

Time zone

This should be the time zone of the city you live in in GMT (Greenwich Mean Time) format. For example, if you live in Saudi Arabia, your time zone is GMT+3, which means the value this parameter must be set to is 3.

Asr shadow factor

The shadow factor for Asr is the length of the shadow relative to an object. If you put a stick in the ground with the length of the stick from the ground is 10cm, and the length of the shadow casted by the sun of the stick is also 10cm, the shadow factor is 1, if the shadow casted by the sun from the sick is 20cm, the shadow factor is 2.

There are two different preferences for this, see the table below for which one you need:

Jurist	Shadow Factor
Shafi'i, Maliki, Ja'fari, Hanbali	1
Hanafi	2

SOURCE: http://praytimes.org/calculation#Asr

Fajr & Isha sun angle

Fajr starts when the sun's light is seen after it was completely invisible, this is called astronomical dawn, while Isha starts when the light of the sun is completely gone.

For this, you can refer to the table below to see which organization suits you

Organization	Angle of the sun (Fajr)	Angle of the sun (Isha)	Region
Muslim World League	18 degrees	17 degrees	Europe, The Far East, Parts of the USA
Egyptian General Authority of Survey	19.5 degrees	17.5 degrees	Africa, Syria, Iraq, Lebanon, Malaysia, Parts of the USA
University Of Islamic Sciences, Karachi	18 degrees	18 degrees	Pakistan, Bangladesh, India, Afghanistan, Parts of Europe
Umm Al-Qura	18.5 Degrees (19 degrees before 1430 hijri)	90 minutes after the Sunset Prayer. 120 minutes (in Ramadan only)	The Arabian Peninsula
Islamic Society of North America	15 degrees	15 degrees	Parts of the USA, Canada, Parts of the UK
Union des Organisations Islamiques de France	12 degrees	12 degrees	France region
Majlis Ugama Islam Singapura	20 degrees	18 degrees	Singapore region

SOURCE: https://fiqhcouncil.org/the-suggested-calculation-method-for-fajr-and-isha/

These parameters can be used accordingly

struct prayers prayers = calculate_prayer_times(TIME_ZONE, LATITUDE, LONGITUDE, ELEVATION, current_date, ASR_SHADOW_FACTOR, FAJR_SUN_ANGLE, ISHA_SUN_ANGLE);

Windows Example

To implement this in your windows Visual Studio project, you must first copy athan_calculator.h and athan_calculator.c to your project. Once this is done, you now need to calculate your current georgian date and put it in the georgian_date structure for use by the calculate_prayer_times function:

#include "athan_calculator.h"
#include <time>

int main() {
  time_t t = time(NULL);
  struct tm lt;

  localtime_s(&lt, &t);

  struct georgian_date current_date = { lt.tm_mday, lt_tm_mon + 1, lt.tm_year + 1900 };

  struct prayers prayers = calculate_prayer_times(3, 21.4241, 39.8173, 277, current_date, 1, 18.5, 18.5);
}

Then you can query a prayer time like so:

prayers.fajr.hour
prayers.fajr.minute
prayers.fajr.second

You can do the same with sunrise, zuhr, asr, maghrib, and isha.

Linux Example

The Linux implementation is the same as Windows, except instead of using localtime_s, you must use localtime_r.

#include "athan_calculator.h"
#include <time>

int main() {
  time_t t = time(NULL);
  struct tm lt;

  localtime_r(&t, &lt);

  struct georgian_date current_date = { lt.tm_mday, lt_tm_mon + 1, lt.tm_year + 19000 };

  struct prayers prayers = calculate_prayer_times(3, 21.4241, 39.8173, 277, current_date, 1, 18.5, 18.5);
}

You can test it with Makkah parameters by cloning this repository and running run_linux.sh:

git clone https://github.com/exploitfreaker/c-prayer-times.git
cd c-prayer-times
chmod +x run_linux.sh
./run_linux.sh

Example usage

Calculator being used for identifying the prayer times in a linux terminal

Calculator being displayed on Waybar(Hyprland)

Calculator being used as an extension for slstatus on DWM (Dynamic Window Manager)