In C++, some types of class members make it tricky to implement a copy assignment operator, operator=. For example references, const members, and… lambdas. Indeed, in the majority of cases, lambdas don’t have an operator=. (In case you’re wondering in what case lambdas have an operator=, it is in C++20 and when they don’t capture anything.) […]
To insert a new entry into an STL set or map, or any of their multi- and unordered- equivalents, we use the insert method: std::map<int, std::string> myMap = // myMap is initialized with stuff… myMap.insert({12, “twelve”}); insert performs the action of inserting the new entry into the container, if that entry wasn’t there already. But insert doesn’t only […]
We’ve been over a various set of smart output iterators over the past few weeks. Today we explore how to combine them and create expressive code. If you’re just joining our series on smart output iterators, you might want to check out this introductory post on smart output iterators. So far, we’ve been combining smart […]
Today’s guest post is written by Vincent Zalzal. Vincent is a software developer working in the computer vision industry for the last 13 years. He appreciates all the levels of complexity involved in software development, from how to optimize memory cache accesses to devising algorithms and heuristics to solve complex applications, all the way to […]
In a previous post, we explored the partition output iterator, that routes data into two directions according to a predicate: the elements that satisfy the predicate to one side, and those that don’t to another side: auto const isEvenPartition = partition([](int n){ return n % 2 == 0; }); std::copy(begin(input), end(input), isEvenPartition(back_inserter(evenNumbers), back_inserter(oddNumbers))); The above code […]
As a logical part of the STL learning resource, here is how the STL has been designed, and how you can design your components to make them benefit from the power of the STL. The design of the STL has been driven by the intention of separating algorithms from data structures. Algorithms include: those in the […]
One thing that is cruelly lacking with std::inserter is that it can do just this: inserting. In some situations this is not enough, in particular for a map: what if an element with the same key is already there? std::inserter, since it calls std::map::insert, will not do anything at all in this case. But maybe we would […]
Smart iterators add great potential to writing expressive code with the STL in C++. And the ones that are proposed natively work particularly well with vectors and with other sequence containers such as deque, list and string. But the situation is not as good for associative containers, such as maps and sets (or their flat- non-standard counterparts). […]
