I’ve been reading up on STL containers in my book on C++, specifically the section on the STL and its containers. Now I do understand each and every one of them have their own specific properties, and I’m close to memorizing all of them… But what I do not yet grasp is in which scenario … Read more
After a lot of investigations with valgrind, I’ve made the conclusion that std::vector makes a copy of an object you want to push_back. Is that really true ? A vector cannot keep a reference or a pointer of an object without a copy ?! Thanks 8 Answers 8
A while ago, I had a discussion with a colleague about how to insert values in STL maps. I preferred map[key] = value; because it feels natural and is clear to read whereas he preferred map.insert(std::make_pair(key, value)). I just asked him and neither of us can remember the reason why insert is better, but I … Read more
What is the cheapest way to initialize a std::vector from a C-style array? Example: In the following class, I have a vector, but due to outside restrictions, the data will be passed in as C-style array: class Foo { std::vector<double> w_; public: void set_data(double* w, int len){ // how to cheaply initialize the std::vector? } … Read more
Why does the Standard define end() as one past the end, instead of at the actual end? 7 Answers 7
Why is std::map implemented as a red-black tree? There are several balanced binary search trees (BSTs) out there. What were design trade-offs in choosing a red-black tree? 6 Answers 6
Every standard container has a begin and end method for returning iterators for that container. However, C++11 has apparently introduced free functions called std::begin and std::end which call the begin and end member functions. So, instead of writing auto i = v.begin(); auto e = v.end(); you’d write auto i = std::begin(v); auto e = … Read more
What is the purpose of std::make_pair? Why not just do std::pair<int, char>(0, ‘a’)? Is there any difference between the two methods? 7 Answers 7
Ok, this is really difficult to confess, but I do have a strong temptation at the moment to inherit from std::vector. I need about 10 customized algorithms for vector and I want them to be directly members of the vector. But naturally I want also to have the rest of std::vector‘s interface. Well, my first … Read more
I mean, aside from its obligating name (the Standard Template Library)… C++ initially intended to present OOP concepts into C. That is: you could tell what a specific entity could and couldn’t do (regardless of how it does it) based on its class and class hierarchy. Some compositions of abilities are more difficult to describe … Read more
