---
description: "Learn more about: <unordered_set>"
title: "<unordered_set>"
ms.date: "11/04/2016"
f1_keywords: ["<unordered_set>"]
helpviewer_keywords: ["unordered_set header"]
ms.assetid: a3364d54-147d-4796-8728-9e62a2e4c226
---
# `<unordered_set>`

Defines the container class templates [unordered_multiset](../standard-library/unordered-multiset-class.md) and [unordered_set](../standard-library/unordered-set-class.md) and their supporting templates.

## Requirements

**Header:** \<unordered_set>

**Namespace:** std

> [!NOTE]
> The \<unordered_set> library also uses the `#include <initializer_list>` statement.

## Members

### Classes

|Name|Description|
|-|-|
|[unordered_multiset Class](../standard-library/unordered-multiset-class.md)|Stores hash table of keys.|
|[unordered_set Class](../standard-library/unordered-set-class.md)|Stores hash table of keys.|

### Functions

|Name|Description|
|-|-|
|[operator!=](../standard-library/unordered-set-operators.md#op_neq)|Tests if the unordered_multiset object on the left side of the operator is not equal to the unordered_multiset object on the right side.|
|[operator==](../standard-library/unordered-set-operators.md#op_eq_eq)|Tests if the unordered_multiset object on the left side of the operator is equal to the unordered_multiset object on the right side.|
|[swap](../standard-library/unordered-set-functions.md#swap_unordered_multiset)|Swaps two multisets.|
|[operator!=](../standard-library/unordered-set-operators.md#op_neq)|Tests if the unordered_set object on the left side of the operator is not equal to the unordered_set object on the right side.|
|[operator==](../standard-library/unordered-set-operators.md#op_eq_eq)|Tests if the unordered_set object on the left side of the operator is equal to the unordered_set object on the right side.|
|[swap](../standard-library/unordered-set-functions.md#swap)|Swaps two sets.|

## See also

[unordered_map Class](../standard-library/unordered-map-class.md)\
[unordered_multimap Class](../standard-library/unordered-multimap-class.md)