Difference between revisions of "cpp/utility/functional/greater"
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{{cpp/utility/functional/navbar}} | {{cpp/utility/functional/navbar}} | ||
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| − | {{dcl header | functional }} | + | {{dcl header|functional}} |
| − | {{dcl rev | + | {{dcl rev multi |
| − | + | |dcl1= | |
template< class T > | template< class T > | ||
struct greater; | struct greater; | ||
| − | + | |since2=c++14|dcl2= | |
| − | + | template< class T = void > | |
| − | template< class T | + | |
struct greater; | struct greater; | ||
}} | }} | ||
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{{dcl end}} | {{dcl end}} | ||
| − | Function object for performing comparisons. | + | Function object for performing comparisons. The main template invokes {{c|operator>}} on type {{tt|T}}. |
===Specializations=== | ===Specializations=== | ||
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{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/utility/functional/dsc greater_void}} | + | {{dsc inc|cpp/utility/functional/dsc greater_void}} |
{{dsc end}} | {{dsc end}} | ||
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| − | + | {{cpp/utility/functional/member types|result=bool|arg1=T|arg2=T}} | |
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===Member functions=== | ===Member functions=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc mem fun | operator() | nolink=true | checks whether the first argument is ''greater'' than the second}} | + | {{dsc mem fun|operator()|nolink=true|checks whether the first argument is ''greater'' than the second}} |
{{dsc end}} | {{dsc end}} | ||
| − | + | {{member|{{small|std::greater::}}operator()|2= | |
| − | {{member | {{small|std::greater::}}operator() | 2= | + | |
{{dcl begin}} | {{dcl begin}} | ||
| − | {{ | + | {{dcla|constexpr=c++14|1= |
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bool operator()( const T& lhs, const T& rhs ) const; | bool operator()( const T& lhs, const T& rhs ) const; | ||
}} | }} | ||
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{{dcl end}} | {{dcl end}} | ||
| − | Checks whether {{ | + | Checks whether {{c|lhs}} is ''greater'' than {{c|rhs}}. |
===Parameters=== | ===Parameters=== | ||
{{par begin}} | {{par begin}} | ||
| − | {{par | lhs, rhs | values to compare}} | + | {{par|lhs, rhs|values to compare}} |
{{par end}} | {{par end}} | ||
===Return value=== | ===Return value=== | ||
| − | {{c| | + | {{c|lhs > rhs}}. |
| − | + | If {{tt|T}} is a pointer type, the result is consistent with the [[cpp/language/operator comparison#Pointer total order|implementation-defined strict total order over pointers]]. | |
| − | + | ||
| + | {{cpp/impldef exception}} | ||
===Possible implementation=== | ===Possible implementation=== | ||
| − | {{eq fun | 1= | + | {{eq fun|1= |
| − | constexpr bool operator()(const T &lhs, const T &rhs) const | + | constexpr bool operator()(const T& lhs, const T& rhs) const |
{ | { | ||
| − | return lhs > rhs; | + | return lhs > rhs; // assumes that the implementation handles pointer total order |
} | } | ||
}} | }} | ||
}} | }} | ||
| + | |||
| + | ===Defect reports=== | ||
| + | {{dr list begin}} | ||
| + | {{dr list item|wg=lwg|dr=2562|std=C++98|before=the pointer total order might be inconsistent|after=guaranteed to be consistent}} | ||
| + | {{dr list end}} | ||
===See also=== | ===See also=== | ||
{{dsc begin}} | {{dsc begin}} | ||
| − | {{dsc inc | cpp/utility/functional/dsc less}} | + | {{dsc inc|cpp/utility/functional/dsc less}} |
| + | {{dsc inc|cpp/utility/functional/ranges/dsc {{SUBPAGENAMEE}}}} | ||
{{dsc end}} | {{dsc end}} | ||
| − | + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | |
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Latest revision as of 21:14, 13 July 2024
| 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. The main template invokes operator> on type T.
Contents |
[edit] Specializations
| (C++14) |
function object implementing x > y deducing parameter and return types (class template specialization) |
[edit] Member types
| Type | Definition |
result_type (deprecated in C++17)(removed in C++20)
|
bool |
first_argument_type (deprecated in C++17)(removed in C++20)
|
T
|
second_argument_type (deprecated in C++17)(removed in C++20)
|
T
|
|
These member types are obtained via publicly inheriting std::binary_function<T, T, bool>. |
(until C++11) |
[edit] Member functions
| operator() |
checks whether the first argument is greater than the second (public member function) |
std::greater::operator()
bool operator()( const T& lhs, const T& rhs ) const; |
(constexpr since C++14) | |
Checks whether lhs is greater than rhs.
Parameters
| lhs, rhs | - | values to compare |
Return value
lhs > rhs.
If T is a pointer type, the result is consistent with the implementation-defined strict total order over pointers.
[edit] Exceptions
May throw implementation-defined exceptions.
Possible implementation
constexpr bool operator()(const T& lhs, const T& rhs) const { return lhs > rhs; // assumes that the implementation handles pointer total order } |
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2562 | C++98 | the pointer total order might be inconsistent | guaranteed to be consistent |
[edit] See also
| function object implementing x < y (class template) | |
| (C++20) |
constrained function object implementing x > y (class) |
