How to define operator< on n-tuple (for example on 3-tuple) so that it satisfy strict weak ordering concept ? I know that boost library has tuple class with correctly defined operator< ...

Does following class breaks strict-weak-ordering (in comparison to regular std::less (So ignoring edge case values such as Nan)) struct LessWithEpsilon { static constexpr double epsilon = some_val...

Comparing pointers to unrelated objects has unspecified results. That would seem to suggest that this program may have undefined behaviour, at the very least because we cannot guarantee a st...

Definition: Let < be a binary relation where a < b means "a is less than b". Let > be a binary relation where a > b means "a is greater than b". So, we assume < and > h...

Is there any existing implementation of Python2 where ordering is transitive? That is, where it's impossible to see this behaviour without creating user-defined types: >>> x < y < z...

Why does C++ standard library work with a comparison function that is strict weak ordering? Why can't it be partial ordering?

I understand that to use std::sort(), the compare function must be strict weak order, otherwise it will crash due to accessing address out of bound. (https://gcc.gnu.org/ml/gcc-bugs/2013-12/msg0033...

[SGI official document] Because of irreflexivity and transitivity, operator< always satisfies the definition of a partial ordering. The definition of a strict weak ordering is stricter, an...

What are the differences between strict/non-strict ordering, weak/non-weak ordering, and partial/total ordering?

From http://stdcxx.apache.org/doc/stdlibref/less-equal.html: You can pass a less_equal object to any algorithm that requires a binary function. For example, the sort() algorithm can accept a binar...

(Note: tuple and tie can be taken from Boost or C++11.) When writing small structs with only two elements, I sometimes tend to choose a std::pair, as all important stuff is already done for that da...

I have some code that compiles fine in VS 10.0 but after inserting a few items into the Orders map below I receive an "invalid operator <" error in Microsoft debug library. My less operator is s...