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Difference between revisions of "cpp/utility/functional/greater"

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Revision as of 06:40, 7 March 2016

 
 
Utilities library
General utilities
Relational operators (deprecated in C++20)
 
Function objects
Function invocation
(C++17)(C++23)
Identity function object
(C++20)
Transparent operator wrappers
(C++14)
(C++14)
(C++14)
(C++14)  
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)
(C++14)

Old binders and adaptors
(until C++17*)
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(until C++17*)
(until C++17*)(until C++17*)(until C++17*)(until C++17*)
(until C++20*)
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(until C++17*)(until C++17*)
(until C++17*)(until C++17*)

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Defined in header <functional>
template< class T >
struct greater;
(until C++14)
template< class T = void >
struct greater;
(since C++14)

Function object for performing comparisons. Unless specialized, invokes operator> on type T.

Contents

Specializations

Implementation-defined strict total order over pointers

A specialization of std::greater for any pointer type yields the implementation-defined strict total order, even if the built-in operator> operator does not.

The implementation-defined strict total order is consistent with the partial order imposed by built-in comparison operators (<=>,(since C++20)<, >, <=, and >=), and consistent among following standard function objects:

(since C++20)

The standard library provides a specialization of std::greater when T is not specified, which leaves the parameter types and return type to be deduced.

function object implementing x > y deducing parameter and return types
(class template specialization) [edit]
(since C++14)

Member types

type definition
result_type(deprecated in C++17) bool
first_argument_type(deprecated in C++17) T
second_argument_type(deprecated in C++17) T

Member functions

operator()
checks if the first argument is greater than the second
(public member function)


std::greater::operator()

bool operator()( const T& lhs, const T& rhs ) const;
(until C++14)
constexpr bool operator()( const T& lhs, const T& rhs ) const;
(since C++14)

Checks whether lhs is greater than rhs.

Parameters

lhs, rhs - values to compare

Return value

true if lhs > rhs, false otherwise.

Exceptions

(none)

Possible implementation

constexpr bool operator()(const T &lhs, const T &rhs) const 
{
    return lhs > rhs;
}