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| Category: containers | | Component type: concept |
Description
A Random Access Container is a ReversibleContainer whose iterator type is a RandomAccessIterator. It provides amortized constant time access to arbitrary elements.
Refinement of
ReversibleContainer
Associated types
No additional types beyond those defined in ReversibleContainer. However, the requirements for the iterator type are strengthened: it must be a RandomAccessIterator.
Notation
X | A type that is a model of Random Access Container |
a, b | Object of type X |
T | The value type of X |
Definitions
Valid expressions
In addition to the expressions defined in ReversibleContainer, the following expressions must be valid.
| Name | Expression | Type requirements | Return type |
| Element access | a[n] | n is convertible to size_type | reference if a is mutable, const_reference otherwise |
Expression semantics
Semantics of an expression is defined only where it is not defined in ReversibleContainer, or where there is additional information.
| Name | Expression | Precondition | Semantics | Postcondition |
| Element access | a[n] | 0 <= n < a.size() | Returns the nth element from the beginning of the container. | |
Complexity guarantees
The run-time complexity of element access is amortized constant time.
Invariants
| Element access | The element returned by a[n] is the same as the one obtained by incrementing a.begin() n times and then dereferencing the resulting iterator. |
Models
Notes
See also
The Iterators, RandomAccessIterator, Sequence
