Comments on: Strongly typed constructors

By: Tomáš Vávra

Tomáš Vávra — Sat, 01 Jul 2017 16:51:00 +0000

In reply to Commander Pirx. This is a very restricting solution. If the only difference is in constructor, then it is not so good idea to have 2 different types representing same thing. For example std::vector - you cannot store a CircleFromRadius or CircleFromDiameter

By: Commander Pirx

Commander Pirx — Fri, 23 Jun 2017 09:40:00 +0000

I usually derive different classes. For example CircleFromRadius(double) and CircleFromDiameter(double).

By: Jonathan Boccara

Jonathan Boccara — Wed, 10 May 2017 16:55:00 +0000

In reply to Łukasz Maciejewski. Good point Łukasz, I changed the title to be more accurate. It's cool that you're learning things. Me too in fact! And if there is something in particular you're curious about, just let me know.

By: Łukasz Maciejewski

Łukasz Maciejewski — Tue, 09 May 2017 18:42:00 +0000

I really like the principle behind the solutuib you present here, but the post itself seems to be misnamed. As far as I know, “named constructors” has a specific meaning and means a static method in class, returning an instance of such class by value – https://isocpp.org/wiki/faq/ctors#named-ctor-idiom . The solution here seems to be a variation on the strong typing theme. This thing aside, I really like the blog and often learn something interesting here, so thanks. 🙂

By: Jonathan Boccara

Jonathan Boccara — Mon, 09 Jan 2017 22:22:00 +0000

In reply to Furkan Üzümcü. Right, sorry didn't realize you were referring to IDE real time doc. I get your point then, fair enough.

By: Furkan Üzümcü

Furkan Üzümcü — Mon, 09 Jan 2017 19:38:00 +0000

In reply to Jonathan Boccara. Don't get me wrong, I'm just trying to understand the motivation better. Most IDEs show the additional information about a function so relying on the IDE to know the type is an option. I think we can also use using Diameter = double; and using Radius = double; to maybe visually indicate it if the variable names are not enough. Maybe I'm just narrowing the situation to just this example and that's blinding me from seeing the big picture.

By: Jonathan Boccara

Jonathan Boccara — Sat, 07 Jan 2017 18:42:00 +0000

In reply to Furkan Üzümcü. Hi Furkan, I get that this relieves the code from accumulating classes, which is good. But how do you know at a call site if the value passed to the circle constructor is a radius or a diameter?

By: Furkan Üzümcü

Furkan Üzümcü — Sat, 07 Jan 2017 09:38:00 +0000

How about this?


class Circle(double radius, double diameter = 0)
    : radius_(diameter == 0 ? radius : diameter / 2)
{
}

This way you don't have to create 2 more classes to just accept two different values for a single constructor.