EqualityComparable

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 Type(s)

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 Guarantee(s)

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

Type(s) Modeling this Concept

• int
• std::vector<T>

Notes

See Also

• LessThanComparable