Today’s guest post is written by Till Heinzel. Till is a physicist-turned-software developer at Luxion Aps in Denmark, who is very interested in expressive C++ and the growth of the language in a more expressive direction. Till can be found online on LinkedIn. First off, I would like to thank Jonathan for creating FluentCpp and […]
Hey all, Here is a little personal announcement. (be right back) (10 min later) Right, so I was saying, I had a little personal announcement to share with you. (be back in a minute) (2 min later) Right! So, the little announcement is: a couple of days ago, I had a little girl! Her name […]
Ranges, STL algorithms and smart output iterators are three libraries that perform operations on collections and make code more expressive. Even if they have some specificities, like zip for ranges and unzip for smart output iterators for example, as we saw when combining ranges with output iterators, they also share features in common, such as transform and filter. […]
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 […]
When you manipulate a collection of objects in C++–which is quite a common thing to do when programming in C++–STL algorithms are your loyal companions to perform operations with expressive code. But the STL algorithms, shipped in the standard library with C++, only apply to collections that are filled at runtime, during the execution of […]
How to apply a function to each of the parameter of another function? For example, consider the following function: template<typename… Args> void g(Args&&… args) { // … } How can we apply a function f to each of the parameters of g? Mixing the code of f with the mechanics of going over all the arguments passed […]
A couple of months (or years?) back, we saw that partitioning in the STL meant tidying up data according to a predicate: all that satisfy the predicate in one group, and all that don’t satisfy the predicate in another group: This is what the STL algorithms std::partition (or std::stable_partition to keep the relative order of elements) do: auto […]
In the Smart Output Iterators library, the unzip output iterator allows to send the various elements contained in tuples or pairs to as many output collections: std::vector<std::tuple<int, int, int>> lines = { {1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12} }; std::vector<int> column1, column2, column3; std::copy(begin(lines), end(lines), fluent::output::unzip(back_inserter(column1), back_inserter(column2), back_inserter(column3))); This […]
Applying a function to each element of a collection and outputting the results into another collection is a very common thing to do, in C++ or elsewhere. In C++, we have the std::transform algorithm to do this, a central piece of the STL algorithms library. To illustrate, consider the following program: #include <algorithm> #include <iterator> […]
Smart output iterators are output iterators that do more than just sending a piece of data from an STL algorithm to a container. They can embed logic that relieves the algorithm of some of its responsibilities. We have already seen examples of smart output iterators that apply a function or filter on a predicate. Now let’s […]
