C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Re: get max of two constant ints as const-expr - without mac          C++Talk.NET Forum Index -> C++ Language (Moderated) View previous topic :: View next topic   Author Message White Wolf Guest Posted: Sun Sep 14, 2003 1:40 am    Post subject: Re: get max of two constant ints as const-expr - without mac manfred wrote: Quote: I'm faced with a situation where i have a hard time replacing the macro version of MAX with the templated version std::max. I've got a bunch of small, constant integers (from a header file, controlled by someone else), and i want to define an array; the size of the array should be the equal to the maximum of the integers. while the macro version compiles fine, the function or templated version fails to compile. any way to get rid of macro MAX here? since everything is known at compile time i would prefer a fixed-size array here, no vector. template <int I, int J> struct your_max { enum e { result = ((I<J)?J:I) }; }; Quote: const int i0 = 2; const int i1 = 4; // more ints... // get the maximum, using a macro #define MYMAX(a, b) ((a) > (b) ? (a) : (b)) const int maxA = MYMAX(i0, i1); // get the maximum, using direct evaluation const int maxB = i0 > i1 ? i0 : i1; // get the maximum, using std::max const int maxC = std::max(i0, i1); // get the maximum, using something like std::max const int& computeMax(const int& i0, const int& i1) { return i0 > i1 ? i0 : i1; } const int maxD = computeMax(i0, i1); // now declare arrays char arrA[your_max<i0,i1>::result]; // ok char arrB[your_max<i0,i1>::result]; // ok char arrC[your_max<i0,i1>::result]; // ok char arrD[your_max<i0,i1>::result]; // ok ;-) -- WW aka Attila [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Sebastian Kapfer Guest Posted: Sun Sep 14, 2003 11:31 am    Post subject: Re: get max of two constant ints as const-expr - without mac On Sat, 13 Sep 2003 19:50:25 -0400, manfred wrote: Quote: I'm faced with a situation where i have a hard time replacing the macro version of MAX with the templated version std::max. I've got a bunch of small, constant integers (from a header file, controlled by someone else), and i want to define an array; the size of the array should be the equal to the maximum of the integers. while the macro version compiles fine, the function or templated version fails to compile. any way to get rid of macro MAX here? since everything is known at compile time i would prefer a fixed-size array here, no vector. You can't use std::max, because it is implemented as a function. But look at this: #include <iostream> #include <string> template< int a, int b > struct static_max { static const int value = (a > b) ? a : b; }; const int const1 = 2, const2 = 5; int main() { std::string b[ static_max< const1, const2 >::value ]; std::cout << sizeof(b) / sizeof(*b) << "n"; return 0; } No macros, but the code is at least as ugly :-) -- Best Regards, | Hi! I'm a .signature virus. Copy me into Sebastian | your ~/.signature to help me spread! [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ Language (Moderated) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.