Using a pointer to a struct in a function

[Kay94]

Hi there,

as written above i'm trying to use a pointer to a struct in a function. But somehow i can't dereference it. Either *pd.name, nor *(pd.name) worked for me (here name is a char array, but it didn't work with any other type as well).
The code is from an exercise, when i try to compile an error occures.

#include <iostream>
#include <cstdlib>
using namespace std;

struct date
{
	int day, month, year;
	char sdate[11];
	long daycount;
};

void getTMJ (date* pd);

int main()
{
...
}

void getTMJ (datum* pd)
{
	cout << *pd.sdatum; // <- error
}

Can anyone tell me, how to correctly do this?
Thanks in advance any effort.

EDIT (after reply): 'datum' must be 'date', wanted to translate it to english but forgot some. this is for future readers.

[TheIdeasMan]

Hi,

Pointers to structs has so much usage that an operator was invented for it. Check out the -> operator - in the reference at top left of this page.

std::cout << pd->sdatum;

Your problem comes from the tighter binding of the . operator over the * operator.

(*pd).sdatum;

So this forces the de-reference of the pointer first, followed by the access to the struct member. Prefer to use the -> operator, it is just easier.

Hope all goes well.

Edit:

Ordinary pointers don't seem to be used that much in modern C++, consider using a reference instead, or for a more advanced topic, smart pointers. Read up about references.

The other thing is the use of STL containers. I imagine that you might want a collection of date data, so if you put them all into a std::vector say, then you can refer to them by their position - just like an array & not need to use pointers or references at all.

[Kay94]

Thanks a lot!
For now i am bound to regular pointers, because the exercises we get in exams are all making use of it. Anyway, it can't be wrong to learn something about it.

[TheIdeasMan]

No worries, hope you have fun & learn heaps :+)