---
description: "Learn more about: References (C++)"
title: "References (C++)"
ms.date: "11/04/2016"
helpviewer_keywords: ["objects [C++], referencing", "references [C++]", "references, to pointers", "declarations, references", "references, declaring", "referencing objects, declarator syntax"]
---
# References (C++)

A reference, like a pointer, stores the address of an object that is located elsewhere in memory. Unlike a pointer, a reference after it's initialized can't be made to refer to a different object or set to null. There are two kinds of references: *lvalue* references, which refer to a named variable and *rvalue* references, which refer to a [temporary object](../cpp/temporary-objects.md). The `&` operator signifies an lvalue reference and the `&&` operator signifies either an rvalue reference, or a universal reference (either rvalue or lvalue) depending on the context.

References may be declared using the following syntax:

> \[*storage-class-specifiers*] \[*cv-qualifiers*] *type-specifiers* \[*ms-modifier*] *declarator* \[**`=`** *expression*]**`;`**

Any valid declarator specifying a reference may be used. Unless the reference is a reference to function or array type, the following simplified syntax applies:

> \[*storage-class-specifiers*] \[*cv-qualifiers*] *type-specifiers* \[**`&`** or **`&&`**] \[*cv-qualifiers*] *identifier* \[**`=`** *expression*]**`;`**

References are declared using the following sequence:

1. The declaration specifiers:

   - An optional storage class specifier.
   - Optional **`const`** and/or **`volatile`** qualifiers.
   - The type specifier: the name of a type.

1. The declarator:

   - An optional Microsoft-specific modifier. For more information, see [Microsoft-Specific Modifiers](../cpp/microsoft-specific-modifiers.md).

   - The **`&`** operator or **`&&`** operator.
   - Optional **`const`** and/or **`volatile`** qualifers.
   - The identifier.

1. An optional initializer.

The more complex declarator forms for pointers to arrays and functions also apply to references to arrays and functions. For more information, see [pointers](../cpp/pointers-cpp.md).

Multiple declarators and initializers may appear in a comma-separated list following a single declaration specifier. For example:

```cpp
int &i;
int &i, &j;
```

References, pointers, and objects may be declared together:

```cpp
int &ref, *ptr, k;
```

A reference holds the address of an object, but behaves syntactically like an object.

In the following program, notice that the name of the object, `s`, and the reference to the object, `SRef`, can be used identically in programs:

## Example

```cpp
// references.cpp
#include <stdio.h>
struct S {
   short i;
};

int main() {
   S  s;   // Declare the object.
   S& SRef = s;   // Declare and initialize the reference.
   s.i = 3;

   printf_s("%d\n", s.i);
   printf_s("%d\n", SRef.i);

   SRef.i = 4;
   printf_s("%d\n", s.i);
   printf_s("%d\n", SRef.i);
}
```

```Output
3
3
4
4
```

## See also

[Reference-Type Function Arguments](../cpp/reference-type-function-arguments.md)<br/>
[Reference-Type Function Returns](../cpp/reference-type-function-returns.md)<br/>
[References to Pointers](../cpp/references-to-pointers.md)