Hi all,
I'm trying to do that, but I get an error, is this possible? If yes in which conditions? Do I have to give it a concrete class type like FooClass<float> ??Code:template <typename T> void FooFunc (vector< FooClass<T> > v) { vector < FooClass<T> >::iterator it; }
The error says "expected ; before it"
Thanks in advance.
Yes, but here iterator is a name that depends on a template name: you know that it is a type name, but it could be say, a member name. You should use typename to disambiguate:
Code:typename vector < FooClass<T> >::iterator it;
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
Oh, I really wasn't aware of this. Thank you for the explanation.
I have another doubt, how can I modify an element in vector and what is the best way to do it?
See the example below, to see what I'm trying to do.
Code:template <typename T> void FooFunc (vector< FooClass<T> > v) { vector < FooClass<T> >::iterator it; FooClass<T> tmp; for (it = v.begin(); it != v.end(); it++) { tmp = changeSomething(*it); } // How to replace the element?? *it = tmp; // fails, because this will change the iterator. // Use copy or replace by having and temporary vector?? // alternatives?? }
I suppose you want:
Or perhaps:Code:for (it = v.begin(); it != v.end(); it++) { *it = changeSomething(*it); }
It's likely that you don't want to pass a copy of the vector to FooFunc either.Code:std::transform(v.begin(), v.end(), v.begin(), changeSomething);
I might be wrong.
Quoted more than 1000 times (I hope).Thank you, anon. You sure know how to recognize different types of trees from quite a long way away.
Yes, you're correct, it should be passed by reference to avoid unnecessary copying.
I will look into std::transform, thanks!
