Some canonized design patterns — Adapter, Factory, Command, Visitor, etc — are approximations of features which are baked into other languages. Off the top of my head: Event-handlers in C# are baked-in versions of the observer pattern. Think about how you’d wire up events in C# if you had to roll your own observer each … Read more
Templates were introduced in the 1988 USENIX paper Parameterized Types for C++ by Bjarne Stroustrup, later incorporated into The Annotated C++ Reference Manual published in 1990 (the version before standardized C++). According to the paper, The <…> brackets are used in preference to the parentheses (…) partly to emphasize the different nature of template arguments … Read more
There are a lot of misconceptions here, both in the question itself and in the several answers. Let me begin by examining the premise of the question. The question is “why do we need the new keyword in C#?” The motivation for the question is this fragment of C++: MyClass object; // this will create … Read more
If you spend a little time in the library, you don’t have to speculate. Here are some statements taken from Dennis Ritchie’s paper on the evolution of C. The context is that Dennis is building on Ken Thompson’s language B, which was implemented on the very tiny PDP-7, a word-addressed machine. Because of growing interest, … Read more
Consider the following function: unsigned sum_evens (unsigned number) { number &= ~1; // ~1 = 0xfffffffe (32-bit CPU) unsigned result = 0; while (number) { result += number; number -= 2; } return result; } Now, let’s play the compiler game and try to compile this by hand. I’m going to assume you’re using x86 … Read more
This is in addition to Terry’s answer. The reason we had to make swap functions in C++ prior to 0x is because the general free-function std::swap was less efficient (and less versatile) than it could be. It made a copy of a parameter, then had two re-assignments, then released the essentially wasted copy. Making a … Read more
I don’t think you’ll get a better answer than “because the author(s) of that language thought it was better that way”. Personally, I think they’re right. I’d hate to find these lines anywhere in the same source file (and refer to the same object+method)… SomeObject.SomeMethod(); … SOMEOBJECT.SOMEMETHOD(); … someObject.someMethod(); … sOmEoBjEcT.sOmEmEtHoD(); I don’t think anyone … Read more
So, the “inheritance” of static members merely looks like namespace pollution That’s right, except that one guy’s pollution is another guy’s added spicy flavouring. I think Martin Fowler, in his work on DSLs, has suggested using inheritance in this way to allow convenient access to static methods, allowing those methods to be used without class … Read more
First, to answer your questions: No. In fact, I argued elsewhere that iterators are the most important/fundamental concept of computer science ever. I (unlike Andrei) also think that iterators are intuitive. Yes, definitely but that shouldn’t come as a surprise. Hmm. Looking at Boost.Range and C++0x – haven’t they already? Andrei’s big contribution here is … Read more