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Equality Comparable


Category: utilities 
Component type: concept 
Description
A type is EqualityComparable if objects of that type can be compared for
equality using operator==, and if operator== is an equivalence relation.
Refinement of
Associated types
Notation
X

A type that is a model of EqualityComparable

x, y, z

Object of type X

Definitions
Valid expressions
Name

Expression

Type requirements

Return type

Equality

x == y


Convertible to bool

Inequality

x != y


Convertible to bool

Expression semantics
Name

Expression

Precondition

Semantics

Postcondition

Equality

x == y

x and y are in the domain of ==



Inequality

x != y

x and y are in the domain of ==

Equivalent to !(x == y)


Complexity guarantees
Invariants
Identity

&x == &y implies x == y

Reflexivity

x == x

Symmetry

x == y implies y == x

Transitivity

x == y and y == z implies x == z

Models
Notes
See also
LessThanComparable.
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