Channel 9 Forums - Tech Off - What's the reasoning behind the behavior of c++ "std::equal"? http://mschnlnine.vo.llnwd.net/d1/Dev/App_Themes/C9/images/feedimage.png Channel 9 Forums - Tech Off - What's the reasoning behind the behavior of c++ "std::equal"? http://channel9.msdn.com/Forums Channel 9 keeps you up to date with the latest news and behind the scenes info from Microsoft that developers love to keep up with. From LINQ to SilverLight – Watch videos and hear about all the cool technologies coming and the people behind them. http://channel9.msdn.com/Forums en Sat, 25 May 2013 00:58:35 GMT Sat, 25 May 2013 00:58:35 GMT Rev9 3 -3 -1 Tech Off - What's the reasoning behind the behavior of c++ "std::equal"? Hi all,

I was just watching the C9 lecture from Stephan about STL algorithms and functors, and I can't really wrap my head around std::equal!

I mean, for me the semantics is a bit strange, since what it does is IMHO more like "isPrefixOf(...)" than an equality check. What was the idea behind implementing std::equal as it is? Is the functionname "equal" not a bit misleading for what it really does?

 

 

Regards,

Chris

]]> http://channel9.msdn.com/Forums/TechOff/Whats-the-reasoning-behind-the-behavior-of-c-stdequal/a2e8fc1c5b514f7d98c8a1210174fbdc#a2e8fc1c5b514f7d98c8a1210174fbdc Sat, 08 Dec 2012 22:37:59 GMT http://channel9.msdn.com/Forums/TechOff/Whats-the-reasoning-behind-the-behavior-of-c-stdequal/a2e8fc1c5b514f7d98c8a1210174fbdc#a2e8fc1c5b514f7d98c8a1210174fbdc McMaiersen 3 http://channel9.msdn.com/Niners/McMaiersen/Discussions/RSS Tech Off - What's the reasoning behind the behavior of c++ "std::equal"? @McMaiersen: Well, it does test two ranges for equality, it's just that the length of the range to be checked is determined by the first iterator pair. Perhaps it is a peculiar design, but it is in line with how most STL functions that operate on two ranges only require you to specify the end of one of them.

Also note that this function crashes (or at least has undefined behavior) if the second range is shorter than the first one, so you have to do sanity checking of the lengths before hand anyway.

]]> http://channel9.msdn.com/Forums/TechOff/Whats-the-reasoning-behind-the-behavior-of-c-stdequal/775b6307731743fba540a12200f08865#775b6307731743fba540a12200f08865 Sun, 09 Dec 2012 14:35:45 GMT http://channel9.msdn.com/Forums/TechOff/Whats-the-reasoning-behind-the-behavior-of-c-stdequal/775b6307731743fba540a12200f08865#775b6307731743fba540a12200f08865 Sven Groot 3 http://channel9.msdn.com/Niners/Sven Groot/Discussions/RSS Tech Off - What's the reasoning behind the behavior of c++ "std::equal"? The "equal" function is in every language for doing a "deep"-check on two objects.

It ensures, that, as the name implies, both objects are actually equal. Consider the following the string construction in class c++:

char *String1 = "Hello World";char *String2= "Hello World";

In more simple languages like VB, you could just compare the strings by "String1 = String2", in more complex languages this wouldn't work because the content will beplaced at two different memory locations, thus an error will be returned.

The "equal" function now does check the real content of the string pointers.

Regards,

Flo

Founder / http://www.lelala.de | Lelala

]]> http://channel9.msdn.com/Forums/TechOff/Whats-the-reasoning-behind-the-behavior-of-c-stdequal/39d02e55ba4c4cc8bf2ea1ac009b7f68#39d02e55ba4c4cc8bf2ea1ac009b7f68 Fri, 26 Apr 2013 09:26:08 GMT http://channel9.msdn.com/Forums/TechOff/Whats-the-reasoning-behind-the-behavior-of-c-stdequal/39d02e55ba4c4cc8bf2ea1ac009b7f68#39d02e55ba4c4cc8bf2ea1ac009b7f68 Lelala 3 http://channel9.msdn.com/Niners/Lelala/Discussions/RSS