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std::unordered_map::at(3) C++ Standard Libary std::unordered_map::at(3)

NAME

std::unordered_map::at - std::unordered_map::at

Synopsis


T& at( const Key& key ); (1) (since C++11)
const T& at( const Key& key ) const; (2) (since C++11)


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.

Parameters


key - the key of the element to find

Return value


Reference to the mapped value of the requested element

Exceptions


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

Complexity


Average case: constant, worst case: linear in size.

See also


operator[] access or insert specified element
(C++11) (public member function)

2022.07.31 http://cppreference.com