greater_equal Struct
A binary predicate that performs the greater-than-or-equal-to operation (operator>=) on its arguments.
template<class Type = void>
struct greater_equal : public binary_function <Type, Type, bool>
{
bool operator()(
const Type& Left,
const Type& Right
) const;
};
// specialized transparent functor for operator>=
template<>
struct greater_equal<void>
{
template<class Type1, class Type2>
auto operator()(Type1&& Left, Type2&& Right) const
-> decltype(std::forward<Type1>(Left)
>= std::forward<Type2>(Right));
};
Parameters
Type, Type1, Type2
Any type that supports an operator>= that takes operands of the specified or inferred types.Left
The left operand of the greater-than-or-equal-to 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 Type1.Right
The right operand of the greater-than-or-equal-to 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 Type2.
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>=.
Remarks
The binary predicate greater_equal<Type> provides a strict weak ordering of a set of element values of type Type into equivalence classes, if and only if this type satisfies the standard mathematical requirements for being so ordered. The specializations for any pointer type yield a total ordering of elements, in that all elements of distinct values are ordered with respect to each other.
Example
// functional_greater_equal.cpp
// compile with: /EHsc
#include <vector>
#include <algorithm>
#include <functional>
#include <cstdlib>
#include <iostream>
int main( )
{
using namespace std;
vector <int> v1;
vector <int>::iterator Iter1;
int i;
v1.push_back( 6262 );
v1.push_back( 6262 );
for ( i = 0 ; i < 5 ; i++ )
{
v1.push_back( rand( ) );
}
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<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,
// specify binary predicate greater_equal<int>( )
sort( v1.begin( ), v1.end( ), greater_equal<int>( ) );
cout << "Resorted vector v1 = ( " ;
for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
cout << *Iter1 << " ";
cout << ")" << endl;
}
Output
Original vector v1 = ( 6262 6262 41 18467 6334 26500 19169 )
Sorted vector v1 = ( 41 6262 6262 6334 18467 19169 26500 )
Resorted vector v1 = ( 26500 19169 18467 6334 6262 6262 41 )
Requirements
Header: <functional>
Namespace: std