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std::unordered_map at() method

// (1) Non const version
T& at( const Key& key );

// (2) Const version
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.

Parameters​

  • key - the key of the element to find

Return value​

Reference to the mapped value of the requested element.

Complexity​

Average case, constant - O(1).
Worst case, linear in size of the containter - O(log size()).

Exceptions​

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

Examples​

important

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