# valarray::operator+=

Visual Studio 2005

Adds the elements of a specified valarray or a value of the element type, element-wise, to an operand valarray.

```
valarray<Type>& operator+=(
const valarray<Type>& _Right
);
valarray<Type>& operator+=(
const Type& _Right
);
```

#### Parameters

_Right

The valarray or value of an element type identical to that of the operand valarray that is to be added, element-wise, to the operand valarray.

## Return Value

A valarray whose elements are the element-wise sum of the operand valarray and _Right.

## Example

```// valarray_op_eadd.cpp
// compile with: /EHsc
#include <valarray>
#include <iostream>

int main( )
{
using namespace std;
int i;

valarray<int> vaL ( 8 ), vaR ( 8 );
for ( i = 0 ; i < 8 ; i += 2 )
vaL [ i ] =  2;
for ( i = 1 ; i < 8 ; i += 2 )
vaL [ i ] =  -1;
for ( i = 0 ; i < 8 ; i++ )
vaR [ i ] =  i;

cout << "The initial valarray is: ( ";
for (i = 0 ; i < 8 ; i++ )
cout << vaL [ i ] << " ";
cout << ")." << endl;

cout << "The initial _Right valarray is: ( ";
for (i = 0 ; i < 8 ; i++ )
cout << vaR [ i ] << " ";
cout << ")." << endl;

vaL += vaR;
cout << "The element-by-element result of "
<< "the sum is the\n valarray: ( ";
for (i = 0 ; i < 8 ; i++ )
cout << vaL [ i ] << " ";
cout << ")." << endl;
}
```

#### Output

```The initial valarray is: ( 2 -1 2 -1 2 -1 2 -1 ).
The initial _Right valarray is: ( 0 1 2 3 4 5 6 7 ).
The element-by-element result of the sum is the
valarray: ( 2 0 4 2 6 4 8 6 ).```

valarray Class

valarray Members