hijri (islamic) calendar problem! - c++

Question

I would convert Gregorian date to Hijri (Islamic) date. After may search on the web, I found a source code to convert it.
I converted the code from Java and PHP to C base.
The implement some times working without any problem. But some days has problem.
I need your help either fix the implement or a available code that will work without any problem!
BTW I found another source code (http://emr.cs.iit.edu/~reingold/calendar.C) that is C++ base. As I don't know C++ if anyone can convert that to C Base or Objective C would be prefect (still not sure this code will work correctly or not).
P.S. You can check the correct date in: islamicfinder.org/Hcal/index.php
void gregorian_to_hijri(int* h_y, int* h_m, int* h_d, int g_y, int g_m, int g_d)
{
int year, month, day;
int zyr;
int zd;
int zm;
int zy;
float zjd;
int zl;
int zn;
int zj;
year = g_y;
month = g_m;
day = g_d;
zyr = year;
zd = day;
zm = month;
zy = zyr;
if((zy > 1582) || ((zy == 1582) && (zm > 10)) || ((zy == 1582) && (zm == 10) && (zd > 14)))
{
zjd = ((1461 * (zy + 4800 + ((zm - 14) / 12))) / 4)
+ ((367 * (zm - 2 - 12 * (((zm - 14) / 12)))) / 12)
- ((3 * (((zy + 4900 + ((zm - 14) / 12)) / 100))) / 4) + zd - 32075;
}
else
{
zjd = 367 * zy - ((7 * (zy + 5001 + ((zm - 9) / 7))) / 4)
+ ((275 * zm) / 9) + zd + 1729777;
}
zl = zjd - 1948440 + 10632;
zn = ((zl - 1) / 10631);
zl = zl - 10631 * zn + 354;
zj = (((10985 - zl) / 5316)) * ((int)((50 * zl) / 17719))
+ ((zl / 5670)) * ((int)((43 * zl) / 15238));
zl = zl - (((30 - zj) / 15)) * (((17719 * zj) / 50))
- ((zj / 16)) * (((15238 * zj) / 43)) + 29;
zm = ((24 * zl) / 709);
zd = zl - ((709 * zm) / 24);
zy = 30 * zn + zj - 30;
*h_y = zy;
*h_m = zm;
*h_d = zd;
}

Answer 1

Assuming this is for a Mac (Cocoa) or iOS (Cocoa Touch) app, since that's where you see Objective C most often, then you can just do something like this:
// Create a Gregorian Calendar
NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
// Set up components of a Gregorian date
NSDateComponents *gregorianComponents = [[NSDateComponents alloc] init];
gregorianComponents.day = 4;
gregorianComponents.month = 12;
gregorianComponents.year = 2010;
// Create the date
NSDate *date = [gregorianCalendar dateFromComponents:gregorianComponents];
[gregorianComponents release];
[gregorianCalendar release];
// Then create an Islamic calendar
NSCalendar *hijriCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSIslamicCivilCalendar];
// And grab those date components for the same date
NSDateComponents *hijriComponents = [hijriCalendar components:(NSDayCalendarUnit |
NSMonthCalendarUnit |
NSYearCalendarUnit)
fromDate:date];
NSLog(#"[In Hijri calendar ->] Day: %ld, Month: %ld, Year:%ld",
[hijriComponents day],
[hijriComponents month],
[hijriComponents year]);
[hijriCalendar release];
If all you want is the current date, then you can skip setting up the gregorian date altogether and just do this:
// Create an Islamic calendar
NSCalendar *hijriCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSIslamicCalendar];
// And grab the date components for the current date
NSDateComponents *hijriComponents = [hijriCalendar components:(NSDayCalendarUnit |
NSMonthCalendarUnit |
NSYearCalendarUnit)
fromDate:[NSDate date]];
[hijriCalendar release];

Answer 2

Have a look at this topic: how to convert hijari date into gregorian date in java script?
The question mentions JavaScript but the top answer seems to have links to implementations in a variety of languages.

Answer 3

You should be able to do this in Objective-C (if that really is an option) using NSCalendar.