Question on boost lambda

[anton.bredikhin]

Hello everybody.

I want to write an unnamed predicate for std::find_if in-place.
If the vector is filled by raw struct, then I can find the target
element like that:


struct C
{
int i;
float f;
}

int main()
{
std::vector<C> v;
// somehow init v

std::find_if(v.begin(), v.end(), &_1->*&C::i == 3);
}


But I cannot make that to work if vector contains boost::shared_ptr to
the C struct.
std::vector<boost::shared_ptr<C> > v;
// somehow init v

std::find_if(v.begin(), v.end(), ???);

Can anyone tell me how can I achieve that?

Thanks
std::find_if(v.begin(), v.end(), /*v->i==3*/ ??)

If the vector is filled by structs without shared_ptr, then I can find
an element like that:

std::find_if(v.begin(), v.end(), &_1->*&C::i == 3);

But I cannot make that code to work with pointers.

Thanks

 

[Kai-Uwe Bux]

Hello everybody.

I want to write an unnamed predicate for std::find_if in-place.
If the vector is filled by raw struct, then I can find the target
element like that:


struct C
{
int i;
float f;
}

int main()
{
std::vector<C> v;
// somehow init v

std::find_if(v.begin(), v.end(), &_1->*&C::i == 3);
}


But I cannot make that to work if vector contains boost::shared_ptr to
the C struct.
std::vector<boost::shared_ptr<C> > v;
// somehow init v

std::find_if(v.begin(), v.end(), ???);

[snip]

Try: &*_1->*&C::i == 3


Best

Kai-Uwe Bux

 

[anton.bredikhin]

Try:  &*_1->*&C::i == 3

Best

Kai-Uwe Bux

It works!
Thanks a lot!