Inheritance diagram for xtd::collections::generic::iequality_comparer< type_t >:

Definition

template<class type_t>
class xtd::collections::generic::iequality_comparer< type_t >

Defines methods to support the comparison of objects for equality.

Definition: template<class type_t>

class iequality_comparer interface_

xtd::collections::generic::iequality_comparer
Defines methods to support the comparison of objects for equality.
Definition iequality_comparer.hpp:34

interface_
#define interface_
This keyword is use to represent an interface.
Definition interface.hpp:58

Header: #include <xtd/collections/generic/iequality_comparer>

Namespace: xtd::collections::generic

Library: xtd.core

Remarks: This interface allows the implementation of customized equality comparison for collections. That is, you can create your own definition of equality for type type_t, and specify that this definition be used with a collection type that accepts the xtd::collections::generic::iequality_comparer <type_t> generic interface. In the xtd framework, constructors of the xtd::collections::generic::dictionary <key_t, value_t> generic collection type accept this interface.; A default implementation of this interface is provided by the xtd::collections::generic::equality_comparer::default_equality_comparer property of the xtd::collections::generic::equality_comparer <type_t> generic class. The xtd::string_comparer class implements xtd::collections::generic::iequality_comparer <type_t> of type xtd::string.; This interface supports only equality comparisons. Customization of comparisons for sorting and ordering is provided by the xtd::collections::generic::icomparer <type_t> generic interface.; We recommend that you derive from the xtd::collections::generic::equality_comparer <type_t> class instead of implementing the xtd::collections::generic::iequality_comparer <type_t> interface, because the xtd::collections::generic::equality_comparer <type_t> class tests for equality using the xtd::iequatable::equals method instead of the xtd::object::equals method. This is consistent with the contains, index_of, last_index_of, and remove methods of the xtd::collections::generic::dictionary <key_t, value_t> class and other generic collections.

Public Methods
virtual auto	equals (const type_t &x, const type_t &y) const noexcept -> bool=0
	Determines whether the specified objects are equal.
virtual auto	get_hash_code (const type_t &obj) const noexcept -> xtd::size=0
	Returns a hash code for the specified object.

Member Function Documentation

◆ equals()

template<class type_t>

virtual auto xtd::collections::generic::iequality_comparer< type_t >::equals	(	const type_t &	x,
		const type_t &	y ) const -> bool

nodiscardpure virtualnoexcept

Determines whether the specified objects are equal.

Parameters

x	The first object of type type_t to compare.
y	The seco,d object of type type_t to compare.

Returns: true if the specified objects are equal; otherwise, false.

Remarks: Implement this method to provide a customized equality comparison for type type_t.

Notes to Implementers: Implementations are required to ensure that if the xtd::collections::generic::iequality_comparer::equals method returns true for two objects x and y, then the value returned by the xtd::collections::generic::iequality_comparer::get_hash_code method for x must equal the value returned for y. The xtd::collections::generic::iequality_comparer::equals method is reflexive, symmetric, and transitive. That is, it returns true if used to compare an object with itself; true for two objects x and y if it is true for y and x; and true for two objects x and z if it is true for x and y and also true for y and z.

Implemented in xtd::basic_string_comparer< char_t >, and xtd::collections::generic::equality_comparer< type_t >.

◆ get_hash_code()

template<class type_t>

virtual auto xtd::collections::generic::iequality_comparer< type_t >::get_hash_code ( const type_t & obj ) const -> xtd::size