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Difference between revisions of "cpp/named req/CopyAssignable"

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< cpp‎ | named req
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{{cpp/concept/navbar}}
 
{{cpp/concept/navbar}}
  
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Specifies that an instance of the type can be copy-assigned (copied).
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Specifies that an instance of the type can be copy-assigned.
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This concept implies {{concept|MoveAssignable}}.
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===Requirements===
 
===Requirements===
  
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The type must implement the following functions:
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The type {{tt|T}} satisfies {{tt|CopyAssignable}} if
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{{member | 1={{dsc small|Type::}}operator= | 2=
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{{ddcl | notes={{mark|One of the variants is sufficient}} | 1=
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* The type {{tt|T}} satisfies {{concept|MoveAssignable}}, and
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Type& Type::operator=( Type& other );
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Type& Type::operator=( const Type& other );
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Type& Type::operator=( volatile Type& other );
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Type& Type::operator=( const volatile Type& other );
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}}
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[[cpp/language/as_operator|Copy assignment operator]]: assigns the contents of {{tt|other}}. The internal state of {{tt|other}} must not be modified.
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Given
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* {{tt|v}}, an [[cpp/language/value_category|lvalue]] expression of type {{tt|T}} or {{tt|const T}} or an [[cpp/language/value_category|rvalue]] expression of type {{tt|const T}}
  
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The following expressions must have the specified effects:
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The following expressions must be valid and have their specified effects
  
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{{dsc begin}}
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{|table class=wikitable
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{{dsc hitem | Expression | Effects}}
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|-
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{{dsc | {{c|1=a = v;}} | {{tt|a}} is equivalent to {{tt|v}}, where {{tt|a}} is an instance of {{tt|Type}} and {{tt|v}} is an instance of {{tt|Type}}. {{tt|v}} must be unchanged.}}
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!Expression||Return type||Return value||Post-conditions
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{{dsc end}}
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|-
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}}
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| {{c|1=t = v}}
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| {{tt|T&}}
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| {{tt|t}}
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| The value of {{tt|t}} is equivalent to the value of {{tt|v}}.
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The value of {{tt|v}} is unchanged.
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|}
  
 
===See also===
 
===See also===

Revision as of 12:00, 28 December 2013

Template:cpp/concept/title Template:cpp/concept/navbar

Specifies that an instance of the type can be copy-assigned.

Requirements

The type T satisfies CopyAssignable if

Given

  • v, an lvalue expression of type T or const T or an rvalue expression of type const T

The following expressions must be valid and have their specified effects

Expression Return type Return value Post-conditions
t = v T& t The value of t is equivalent to the value of v.

The value of v is unchanged.

See also

(C++11)(C++11)(C++11)
 checks if a type has a copy assignment operator
(class template) [edit]
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