operator-overloading of nested class inside a template class

[Gerhard Pfeiffer]

Hi,

I'm trying to implement a data-structure and have an iterator for it. Now I've
got a problem impleneting the operator+. I tried to isolate the problem:

template<int DIM, typename Tclass data_structure {
private:
int data[256];
public:
class iterator {
public:
int index;
};
};

template<int DIM, typename T>
data_structure<DIM, T>::iterator
operator+(data_structure<DIM, T>::iterator it, int n) {
iterator ret();
ret.index = it.index + n;
}

and g++ gives me this error:
bla.cpp:13: error: expected constructor, destructor, or type conversion before
'operator'

I just don't see, what I'm doing wrong here. Any hints would be appreciated.

Ciao,
Gerhard

[Victor Bazarov]

Gerhard Pfeiffer wrote:

Hi,

I'm trying to implement a data-structure and have an iterator for it.
Now I've got a problem impleneting the operator+. I tried to isolate
the problem:

template<int DIM, typename Tclass data_structure {
private:
int data[256];
public:
class iterator {
public:
int index;
};
};

template<int DIM, typename T>
data_structure<DIM, T>::iterator
operator+(data_structure<DIM, T>::iterator it, int n) {
iterator ret();

^^^^^^^^^^^^^^^^^^^^^^
This is a declaration of a function. Drop the parentheses.

ret.index = it.index + n;
}

and g++ gives me this error:
bla.cpp:13: error: expected constructor, destructor, or type
conversion before 'operator'

I just don't see, what I'm doing wrong here. Any hints would be
appreciated.

Read the FAQ. All of it.

V
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[David Harmon]

On 14 Sep 2006 18:04:59 GMT in comp.lang.c++, Gerhard Pfeiffer
<[e-mail],

>template<int DIM, typename T>
data_structure<DIM, T>::iterator
operator+(data_structure<DIM, T>::iterator it, int n) {
iterator ret();
ret.index = it.index + n;
}

iterator is a type dependent on the template parameter; "typename"
is required.

template<int DIM, typename T>
typename data_structure<DIM, T>::iterator
operator+(typename data_structure<DIM, T>::iterator it, int n) {
iterator ret();
ret.index = it.index + n;
}

[Victor Bazarov]

David Harmon wrote:

On 14 Sep 2006 18:04:59 GMT in comp.lang.c++, Gerhard Pfeiffer
<[e-mail],

>template<int DIM, typename T>
data_structure<DIM, T>::iterator
operator+(data_structure<DIM, T>::iterator it, int n) {
iterator ret();
ret.index = it.index + n;
}

iterator is a type dependent on the template parameter; "typename"
is required.

template<int DIM, typename T>
typename data_structure<DIM, T>::iterator
operator+(typename data_structure<DIM, T>::iterator it, int n) {
iterator ret();

'ret' is still a function here...

ret.index = it.index + n;
}

V
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