binary_negate Class
A template class providing a member function that negates the return value of a specified binary function.
template<class Operation>
class binary_negate
: public binary_function <
typename Operation::first_argument_type,
typename Operation::second_argument_type,
bool>
{
public:
explicit binary_negate(
const Operation& _Func
);
bool operator()(
const typename Operation::first_argument_type& _Left,
const typename Operation::second_argument_type& _Right
) const;
};
Parameters
_Func
The binary function to be negated._Left
The left operand of the binary function to be negated._Right
The right operand of the binary function to be negated.
Return Value
The negation of the binary function.
Remarks
The template class stores a copy of a binary function object _Func. It defines its member function operator() as returning !_Func(_Left, _Right).
The constructor of binary_negate is rarely used directly. The helper function not2 is usually preferred to declare and use the binary_negator adaptor predicate.
Example
// functional_binary_negate.cpp
// compile with: /EHsc
#define _CRT_RAND_S
#include <stdlib.h>
#include <vector>
#include <algorithm>
#include <functional>
#include <iostream>
int main( )
{
using namespace std;
vector <unsigned int> v1;
vector <unsigned int>::iterator Iter1;
unsigned int i;
v1.push_back( 6262 );
v1.push_back( 6262 );
unsigned int randVal = 0;
for ( i = 0 ; i < 5 ; i++ )
{
rand_s(&randVal);
v1.push_back( randVal );
}
cout << "Original vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
// To sort in ascending order,
// use default binary predicate less<unsigned int>( )
sort( v1.begin( ), v1.end( ) );
cout << "Sorted vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
// To sort in descending order,
// use the binary_negate function
sort( v1.begin( ), v1.end( ),
binary_negate<less<unsigned int> >(less<unsigned int>( ) ) );
// The helper function not2 could also have been used
// in the above line and is usually preferred for convenience
// sort( v1.begin( ), v1.end( ), not2(less<unsigned int>( ) ) );
cout << "Resorted vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
}
Original vector v1 = ( 6262 6262 2233879413 2621500314 580942933 3715465425 3739828298 ) Sorted vector v1 = ( 6262 6262 580942933 2233879413 2621500314 3715465425 3739828298 ) Resorted vector v1 = ( 3739828298 3715465425 2621500314 2233879413 580942933 6262 6262 )
Requirements
Header: <functional>
Namespace: std
See Also
Reference
Thread Safety in the Standard C++ Library