C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Re: Official c++ 64-bit integer data type          C++Talk.NET Forum Index -> C++ language, library and standards View previous topic :: View next topic   Author Message cody Guest Posted: Sun Jul 13, 2003 6:01 am    Post subject: Re: Official c++ 64-bit integer data type Quote: Unfortunatly using the same names will not increase portability where it matters: int32_t = int16_t + int16_t; This example will have different results depending on the sizeof(int). you add datatypes together???? what do you mean here? -- cody [Freeware, Games and Humor] www.deutronium.de.vu || www.deutronium.tk --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Michiel Salters Guest Posted: Mon Jul 14, 2003 7:10 pm    Post subject: Re: Official c++ 64-bit integer data type [email]deutronium (AT) gmx (DOT) net[/email] ("cody") wrote in message news:<beqfj3$7u1ck$1 (AT) ID-176797 (DOT) news.uni-berlin.de>... Quote: Unfortunatly using the same names will not increase portability where it matters: int32_t = int16_t + int16_t; This example will have different results depending on the sizeof(int). you add datatypes together???? what do you mean here? Adding variables of the specified type together, e.g. int16_t a = 1<<14; int16_t b = 1<<14; int32_t c = a + b; The obvious result would be c = 1<<15, but in the addition the types will be promoted to int. The result of the addition will also be an int. Whether or not that overflows still depends on the exact bitwidth of an int. c==-(1<<15) could occur if ints are 16 bits. Regards, -- Michiel Salters --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Richard Corden Guest Posted: Mon Jul 14, 2003 9:58 pm    Post subject: Re: Official c++ 64-bit integer data type Quote: int32_t = int16_t + int16_t; This example will have different results depending on the sizeof(int). you add datatypes together???? what do you mean here? Sorry for the poor example... void foo (int16_t a, int16_t b) { int32_t result; result = a + b; } So, the value of result may be different for different sizes of int. Regards Richard. -- Richard Corden To reply remove 's' from address --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top cody Guest Posted: Thu Jul 17, 2003 1:43 am    Post subject: Re: Official c++ 64-bit integer data type Quote: void foo (int16_t a, int16_t b) { int32_t result; result = a + b; } you mean in the case if int would be 8 bits then: 300 + 200 = 88 and not 600 because every integral expression where not type ios explicitely specified results int the int-type? -- cody [Freeware, Games and Humor] www.deutronium.de.vu || www.deutronium.tk --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top Philippe Mori Guest Posted: Mon Jul 21, 2003 6:32 pm    Post subject: Re: Official c++ 64-bit integer data type ""cody"" <deutronium (AT) gmx (DOT) net> a écrit dans le message de news:bf466n$auf1n$1 (AT) ID-176797 (DOT) news.uni-berlin.de... Quote: void foo (int16_t a, int16_t b) { int32_t result; result = a + b; } you mean in the case if int would be 8 bits then: 300 + 200 = 88 and not 600 because every integral expression where not type ios explicitely specified results int the int-type? -- If you want portable code then you would write something like: int32_t foo(int16_t a, int16_t bn) { int32_t result = a; result += b; return result; } --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.jamesd.demon.co.uk/csc/faq.html ] Back to top cody Guest Posted: Tue Jul 22, 2003 10:56 pm    Post subject: Re: Official c++ 64-bit integer data type Quote: If you want portable code then you would write something like: int32_t foo(int16_t a, int16_t bn) { int32_t result = a; result += b; return result; } better would be: inline int32_t foo(int16_t a, int16_t bn) { return (int32_t)a + b; } :-D -- cody [Freeware, Games and Humor] www.deutronium.de.vu || www.deutronium.tk --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. 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