C++ Passing std::vector< boost::shared_ptr< foo > >

Question

I am currently learning the basics of the STL and boost libraries and wanted some assistance. Let me first describe where I am at I want to construct a vector of shared_ptrs of say some class foo. Previously I had an array or pointers and was required to use new and delete to handle memory and thought the transition to vectors and smart pointers would be a good idea. I currently have something like:

class foo{
 ....
}

int main(){
 std::vector< boost::shared_ptr< foo > > vec_ptr;
 vec_ptr.push_back(boost::make_shared<foo>);
 ....
} 

Now I would like to know how to best pass this vector in two situations: - Into a function. - Into the constructor of a class object (which via the initialisation list initialises the object.

Into a function I am guessing that it is best passed by reference, as in:

void func(std::vector< boost::shared_ptr < foo > >& vec_ptr_in_func){
  ....
}

Into a class constructor I am not sure my initial guess was something like

class vec_class{
 vec_class(std::vector< boost::shared_ptr < foo > >& vec_ptr_in_class_)
  : vec_ptr_in_class(vec_ptr_in_class_){...}
}

But this seems to be giving errors along the lines of:

no matching function for call to vec_class::vec_class(std::vector< boost::shared_ptr < foo >, std::allocator<boost::shared_ptr< foo > > >) 

Answer 1

1. For a function pass it like

    // If you intend to modify the vec_ptr_in_func void func(std::vector< boost::shared_ptr < foo > >& vec_ptr_in_func){ } // If you intend to not modify the vec_ptr_in_func void func(const std::vector< boost::shared_ptr < foo > >& vec_ptr_in_func){ } 

2. Pass it by const-reference for the constructor.