The Ranges library proposal has been accepted for C++20 at the San Diego meeting of the standard committee in November last year. The library provides components for handling ranges of values aimed at simplifying our code. Unfortunately, the Ranges library is not very well documented, which makes it harder to grasp for those that want to learn it. This post is intended as an introduction based on examples of code written with and without Ranges.
std::equal_range is a general purpose standard algorithm used to find a sub-range of values in a given sorted or at least partitioned range. In this post, I will explain how the algorithm works.
The C++ community has worked hard in the past decade and more to move the language forward, to enrich but also simplify it, and to adopt new paradigms and coding styles. Yet, a single topic, a simple matter of style is splitting the community, in a pure Swiftian manner: the use of the const qualifier that some prefer it on the left of what it modifies, as it has been the de facto standard for decades, and which is now called West const, or to the right of that it modifies, that is a style that more and more people are adopting, and which is now called East const. I don’t particularly like this terms, I would rather use left const and right const, but if this is what the community prefers to use let’s call them so for consistency.
I have been working lately on a C++ library for handling monetary values, currencies, rounding and other related features. It is called moneycpp and it’s a C++ 17 header-only, cross-platform library available on GitHub.
The library is intended for being used in a variety of types of application including ERP systems, banking, finance, insurance, games, and others.
The following is a list of its core requirements:
Unit testing is usually used for testing public types and members. However, there are cases when you might need to test types or members that are not public. These could be internal classes or private helper methods, for instance. Whether that is proper unit testing or beyond its scope is not a discussion that I want to get into here. However, in this post, I will show how you can unit test non-public types and members from .NET assemblies.
When faced with the need for testing non-public types and members you can use several approaches:
- change the accessibility to public; you can do that perhaps only for debug builds and keep the intended accessibility in release builds by using conditional compilation.
- provide public members of a class that invoke private ones;
- use reflection.
The first solutions involve changing the API only for the sake of the testing. The last solution avoids that but requires more work. To help with that, the Visual Studio unit testing framework provides some helper types that enable you to focus on the actual testing and be less concerned about the reflection details.
Here is my list of good reads from September:
Class template argument deduction is a useful feature in C++17 that helps developers to simplify the code by avoiding writing the template argument list when initializing objects of class templates (or when performing function-style casts). The compiler provides an implicit set of deduction guides, which are fictional function templates for a hypothetical class and uses them to perform template argument deduction and overload resolution. However, you can extend this set of deduction guides with your own, and in some cases, such as for aggregate types, you need to do so.
Here is my list of good reads from August:
A CRON expression is a string composed of six fields (in some implementation seven), separated by a whites space, representing a time schedule. CRON expressions are used in various job schedulers (such as the Linux job scheduler, the Quartz scheduler, Azure scheduler for functions, etc.). Recently, I have written a C++ library for parsing such expressions and determining the next occurrence of the scheduled time. The library is called croncpp. It is written in C++17, is header-only, open-source and cross-platform, and can be found on GitHub.
A couple of weeks ago, version 15.8 of Visual Studio 2017 was finally released. You can read here about the new things available in this version. In this post, I will discuss five productivity features available for C++ development.