divides Struct

[アーティクル]
01/02/2018

The latest version of this topic can be found at divides Struct.

A predefined function object that performs the division operation ( operator/) on its arguments.

Syntax

template <class Type = void>
struct divides : public binary_function <Type, Type, Type>  
{
    Type operator()(
    const Type& Left,
    const Type& Right) const;

 };

// specialized transparent functor for operator/
template <>
struct divides<void>  
{
template <class T, class U>
auto operator()(T&& Left, U&& Right) const
 ->  
decltype(std::forward<T>(Left)*/ std::forward<U>(Right));

 };

Parameters

Type, T, U
A type that supports an operator/ that takes operands of the specified or inferred types.

Left
The left operand of the division operation. The unspecialized template takes an lvalue reference argument of type Type. The specialized template does perfect forwarding of lvalue and rvalue reference arguments of inferred type T.

Right
The right operand of the division operation. The unspecialized template takes an lvalue reference argument of type Type. The specialized template does perfect forwarding of lvalue and rvalue reference arguments of inferred type U.

Return Value

The result of Left``/``Right. The specialized template does perfect forwarding of the result, which has the type that's returned by operator/.

Example

// functional_divides.cpp  
// compile with: /EHsc  
#include <vector>  
#include <functional>  
#include <algorithm>  
#include <iostream>  
  
using namespace std;  
  
int main( )  
{  
   vector <double> v1, v2, v3 (6);  
   vector <double>::iterator Iter1, Iter2, Iter3;  
  
   int i;  
   for ( i = 0 ; i <= 5 ; i++ )  
   {  
      v1.push_back( 7.0 * i );  
   }  
  
   int j;  
   for ( j = 1 ; j <= 6 ; j++ )  
   {  
      v2.push_back( 2.0 * j);  
   }  
  
   cout << "The vector v1 = ( " ;  
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )  
      cout << *Iter1 << " ";  
   cout << ")" << endl;  
  
   cout << "The vector v2 = ( " ;  
   for ( Iter2 = v2.begin( ) ; Iter2 != v2.end( ) ; Iter2++ )  
      cout << *Iter2 << " ";  
   cout << ")" << endl;  
  
   // Finding the element-wise quotients of the elements of v1 & v2  
   transform ( v1.begin( ), v1.end( ), v2.begin( ), v3.begin ( ),   
      divides<double>( ) );  
  
   cout << "The element-wise quotients are: ( " ;  
   for ( Iter3 = v3.begin( ) ; Iter3 != v3.end( ) ; Iter3++ )  
      cout << *Iter3 << " ";  
   cout << ")" << endl;  
}  
  
/* Output:  
The vector v1 = ( 0 7 14 21 28 35 )  
The vector v2 = ( 2 4 6 8 10 12 )  
The element-wise quotients are: ( 0 1.75 2.33333 2.625 2.8 2.91667 )  
*/

Requirements

Header: <functional>

Namespace: std

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