# &+=(_:_:)

Adds two values and stores the result in the left-hand-side variable, wrapping any overflow.

Available because

`Self`

conforms to`FixedWidthInteger`

.

`static func &+= (lhs: inout Self, rhs: Self)`

## Parameters

- lhs
The first value to add.

- rhs
The second value to add.

## Overview

The masking addition assignment operator (`&+=`

) silently wraps any overflow that occurs during the operation. In the following example, the sum of `100`

and `121`

is greater than the maximum representable `Int8`

value, so the result is the partial value after discarding the overflowing bits.

```
var x: Int8 = 10
x &+= 21
// x == 31
var y: Int8 = 100
y &+= 121
// y == -35 (after overflow)
```

For more about arithmetic with overflow operators, see Overflow Operators in *The Swift Programming Language*.