Am 15.07.2010 um 05:13 schrieb Jennifer Usher:
> I am trying to port some C code libraries into a program I am working on and I am a bit puzzled how to convert this function declaration:
>
> void dateYMD(int nDate, int &year, int &month, int &day, calendar dateSystem=cal_Gregorian)
That code uses C++ features. The "&" is a reference, essentially the same as the "*"-operator, just that you can use it without dereferencing. I.e. to convert C++ references to C (and thus Objective-C) pointers, you'd take:
void main()
{
int x = 100;
changeX( x );
}
void changeX( int &x )
{
x = 15;
}
and turn it into
void main()
{
int x = 100;
changeX( &x );
}
void changeX( int *x )
{
*x = 15;
}
Similarly for a struct MyStruct { int number }; you'd turn:
void main()
{
MyStruct x;
changeX( x );
}
void changeX( MyStruct &x )
{
x.number = 15;
}
into:
void main()
{
struct MyStruct x;
changeX( &x );
}
void changeX( MyStruct *x )
{
x->number = 15; // or (*x).number = 15;
}
Similarly, the calendar dateSystem=cal_Gregorian is a default parameter. That is, when calling this function in C++, people can leave out that parameter, and the compiler will automatically generate code as if you had passed cal_Gregorian. To fix that, you'd just remove that part and everywhere you call that function, you'd pass cal_Gregorian as an additional last parameter. Alternately, you can create another function that doesn't have the last parameter:
void dateYMDGregorian(int nDate, int *year, int *month, int *day)
{
dateYMD(nDate,year,month,day,cal_Gregorian);
}
And then just change the call sites to call dateYMDGregorian. Alternately, you can turn on the Objective-C++ compiler, which lets you mix C++ and Objective C in the same file.
-- Uli Kusterer
"The Witnesses of TeachText are everywhere..."
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