< cpp‎ | container‎ | map
T& at( const Key& key );
const T& at( const Key& key ) const;

Returns a reference to the mapped value of the element with key equivalent to key. If no such element exists, an exception of type std::out_of_range is thrown.


[edit] Parameters

key - the key of the element to find

[edit] Return value

Reference to the mapped value of the requested element.

[edit] Exceptions

std::out_of_range if the container does not have an element with the specified key

[edit] Complexity

Logarithmic in the size of the container.

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 464 C++98 map did not have this member function added
LWG 703 C++98 the complexity requirement was missing added

[edit] See also

access or insert specified element
(public member function) [edit]