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# valarray::operator-=

Visual Studio 2005

Subtracts the elements of a specified valarray or a value of the element type, element-wise, from 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 subtracted, element-wise, from the operand valarray.

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

```// valarray_op_esub.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 ] =  10;
for ( i = 1 ; i < 8 ; i += 2 )
vaL [ i ] =  0;
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 difference is the\n valarray: ( ";
for ( i = 0 ; i < 8 ; i++ )
cout << vaL [ i ] << " ";
cout << ")." << endl;
}
```

#### Output

```The initial valarray is: ( 10 0 10 0 10 0 10 0 ).
The initial _Right valarray is: ( 0 1 2 3 4 5 6 7 ).
The element-by-element result of the difference is the
valarray: ( 10 -1 8 -3 6 -5 4 -7 ).```

valarray Class

valarray Members