operator<< (<valarray>)

Left shifts the bits for each element of a valarray a specified number of positions or by an element-wise amount specified by a second valarray.

template<class Type>
   valarray<Type> operator<<(
      const valarray<Type>& _Left,
      const valarray<Type>& _Right
   );
template<class Type>
   valarray<Type> operator<<(
      const valarray<Type>& _Left,
      const Type& _Right
   );
template<class Type>
   valarray<Type> operator<<(
      const Type& _Left,
      const valarray<Type>& _Right
   );

Parameters

• _Left
  The value to be shifted or the valarray whose elements are to be shifted.

• _Right
  The value indicating the amount of left shift or valarray whose elements indicate the element-wise amount of left shift.

Return Value

A valarray whose elements have been shifted left by the specified amount.

Remarks

Signed numbers have their signs preserved.

Example

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

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

   valarray<int> vaL ( 8 ), vaR ( 8 );
   valarray<int> vaNE ( 8 );
   for ( i = 0 ; i < 8 ; i += 2 )
      vaL [ i ] =  1;
   for ( i = 1 ; i < 8 ; i += 2 )
      vaL [ i ] =  -1;
   for ( i = 0 ; i < 8 ; i++ )
      vaR [ i ] =  i;
   
   cout << "The initial Left 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;

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

The initial Left valarray is: ( 1 -1 1 -1 1 -1 1 -1 ).
The initial Right valarray is: ( 0 1 2 3 4 5 6 7 ).
The element-by-element result of the left shift is the
 valarray: ( 1 -2 4 -8 16 -32 64 -128 ).

Requirements

Header: <valarray>

Namespace: std