在C ++上通过引用传递值

Question

I am trying to understand what the arguments are for this method in a class from ns-3.

void ns3::OnOffHelper::SetAttribute ( std::string name, const AttributeValue & value )

I was able to pass the first argument, but I am not sure what the second argument should be. Does it mean I have to pass a pointer value for the second argument?

Thanks, BZ

Answer 1

No, pass it how you would pass a normal variable. The difference is that the variable is passed by reference and not by value so any changes the function SetAttribute makes to value will still be visible once the function returns. In this case however, its const & which promises you that it won't change value , it will only use it's information. This is usually done to prevent expensive copies (before C++11).