C++ concepts: EqualityComparable
From cppreference.com
The type must work with == operator and the result should have standard semantics.
Requirements
The type T satisfies EqualityComparable if
Given
-
a,b, andc, expressions of typeTorconst T
The following expressions must be valid and have their specified effects
| Expression | Return type | Requirements |
|---|---|---|
a == b
|
implicitly convertible to bool | Establishes equivalence relation with the following properties:
|
Notes
To satisfy this requirement, types that do not have built-in comparison operators have to provide a user-defined operator==.
For the types that are both EqualityComparable and LessThanComparable, the C++ standard library makes a distinction between equality, which is the value of the expression a == b and equivalence, which is the value of the expression !(a < b) && !(b < a).