[class.eq]

# 11 Classes [[class]](./#class)

## 11.10 Comparisons [[class.compare]](class.compare#class.eq)

### 11.10.2 Equality operator [class.eq]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/classes.tex#L6693)

A defaulted equality operator function ([[over.binary]](over.binary "12.4.3 Binary operators"))
shall have a declared return type bool[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/classes.tex#L6697)

A defaulted == operator function for a class C is defined as deleted
unless, for each xi in the expanded list of subobjects
for an object x of type C,xi == xi is usable ([[class.compare.default]](class.compare.default "11.10.1 Defaulted comparison operator functions"))[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/classes.tex#L6705)

The return value of a defaulted == operator function
with parameters x and y is determined
by comparing corresponding elements xi and yi in the expanded lists of subobjects for x and y (in increasing index order)
until the first index i where xi == yi yields a result value which,
when contextually converted to bool, yields false[.](#3.sentence-1)

The return value is false if such an index exists
and true otherwise[.](#3.sentence-2)

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/classes.tex#L6717)

[*Example [1](#example-1)*: struct D {int i; friend bool operator==(const D& x, const D& y) = default; // OK, returns x.i == y.i}; — *end example*]