Ordinary C ++ programmers vs literary C ++ programmers

The original post was originally posted in the QQ space:Ordinary C ++ programmers vs literary C ++ programmers,Http://user.qzone.qq.com/31731705/blog/1323153107 

I saw a C ++ post on BBS, C ++ has gone astray?It reminds me of ordinary youth and literary youth.

See this classic Nb
Program to find the number of BITs
. J

Common C ++
Programmer

namespace traditional { int bits_of(int remain) { if (remain) return 1+bits_of( remain>>1 ); return 0; } int bits_of(void) { return bits_of(~(int)0); } } 

 

Literature and art C ++
Programmer

namespace modern { template<int,typename THEN, typename ELSE> struct IF { typedefTHEN type; }; template<typename THEN, typename ELSE> struct IF<0,THEN,ELSE> { typedef ELSE type; }; template<typename T, T X> struct zero { static const Tvalue = X; }; template<typename T, T X> struct bits_of { typedef typenameIF<X, bits_of<T,(X>>1)>, zero<T,0> >::type type; static const Tvalue = type::value + !!X; }; }

Unit Test of Wen Qing,

typedef int a0[bits_of<int,0>::value==0? 1: -1];typedef int a1[bits_of<int,1>::value==1? 1: -1];typedef int a2[bits_of<int,2>::value==2? 1: -1];typedef int a3[bits_of<int,3>::value==2? 1: -1];typedef int a4[bits_of<int,4>::value==3? 1: -1];typedef int a7[bits_of<int,7>::value==3? 1: -1];typedef int a8[bits_of<int,8>::value==4? 1: -1];typedef int a15[bits_of<int,15>::value==4? 1: -1];typedef int a16[bits_of<int,16>::value==5? 1: -1];  

Category 3 C ++
Programmer

Namespace third_party {// are you sure you can understand? }