Obscure C++ Features [from the newsletter]
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Thank elephant for that! Use most of those, and you deserve to be shot...
The universe is composed of electrons, neutrons, protons and......morons. (ThePhantomUpvoter)
That might be so, but I think their program still would execute, and not the person :sigh:
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I will confess to having used two of those practices, but I washed my hands afterwards.
Software Zen:
delete this; -
I remember the redefinition of keywords: a friend of mine has some headers that let him compile and run simple Pascal programs using C.
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Most of these(except templates tricks etc.) has nothing to do with C++, but are inherited C constructions. And some of them are quite useful in system programing.
There is only one Vera Farmiga and Salma Hayek is her prophet! Advertise here – minimum three posts per day are guaranteed.
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I was quite delighted to discover among the alternate operator tokens keywords for &&, || and !. I never really liked these "rude" logical operators and this gave me a sufficient incentive to switch to the nicer litteral representation. Isn't that beautiful ?
if (i < N and not Odd(A[i]))
I will not embrace the tokens for &, | and ~, as these correspond to bitwise operators which are more arithmetic in essence and compare to the usual +, -, *, /. Even less the _eq forms, which in my opinion are misnomers: f.i. or_eq should read bitor_eq.
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Obscure, you say? How about ... The comma operator; result = a , b; computes a, discards it, computes b, and assigns b to result. C++ (and C)'s hidden operator language; Conditional operator result = a ? b : c; evaluates a, then evaluates b if a is nonzero, or else evaluates c. The comma operator above as a way to do sequences as an expression. All C++ is missing is a value-returning loop. I do second the motion for method pointers as the most obscure and underused (but useful) aspect of C++. Or maybe virtual multiple inheritance, which can get mind-bendingly complex in examples I've seen in the wild.
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I remember the redefinition of keywords: a friend of mine has some headers that let him compile and run simple Pascal programs using C.
I remember this one from a C++ course I took:
#define ;; ever;
Which of course allowed infinite for loops to be coded as
for(ever) {...}
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I remember this one from a C++ course I took:
#define ;; ever;
Which of course allowed infinite for loops to be coded as
for(ever) {...}
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I've tried my hand at redefining the comma operator[^] after I've seen it in Blitz++ and Boost::Spirit (!). But I eventually discarded the idea due to various problems. I tried metaprogramming (the factorial implementation), but only for instructional purposes, not for real use. What I actually use in real code: 1. I do overload ++ and -- (pre and postfix both) a lot. 2. I did use in-place new and explicit call of destructor for the implementation of a memory pool. I don't see anything wrong with that as there really is no other good way to allocate memory for C++ objects and ensure proper initialization. (and cleaning up after release, without freeing the memory) 3. I do use static methods occasionally. But I wonder why they are on the "obscure features list" to start with. Of the remaining features listed in that article, I would indeed consider them obscure as I either wasn't aware them, or never found a useful application. ;) Passing a function as a template parameter is the only feature of these that I would consider useful, although I haven't actually used it myself. If you want an equally or more obscure feature, the only thing I can think of from the top of my head are trigraphs. (see http://www.gotw.ca/gotw/086.htm[^] - it also contains examples for some items already on the list)
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I've tried my hand at redefining the comma operator[^] after I've seen it in Blitz++ and Boost::Spirit (!). But I eventually discarded the idea due to various problems. I tried metaprogramming (the factorial implementation), but only for instructional purposes, not for real use. What I actually use in real code: 1. I do overload ++ and -- (pre and postfix both) a lot. 2. I did use in-place new and explicit call of destructor for the implementation of a memory pool. I don't see anything wrong with that as there really is no other good way to allocate memory for C++ objects and ensure proper initialization. (and cleaning up after release, without freeing the memory) 3. I do use static methods occasionally. But I wonder why they are on the "obscure features list" to start with. Of the remaining features listed in that article, I would indeed consider them obscure as I either wasn't aware them, or never found a useful application. ;) Passing a function as a template parameter is the only feature of these that I would consider useful, although I haven't actually used it myself. If you want an equally or more obscure feature, the only thing I can think of from the top of my head are trigraphs. (see http://www.gotw.ca/gotw/086.htm[^] - it also contains examples for some items already on the list)
