24 Containers library [containers]

24.5 Unordered associative containers [unord]

24.5.4 Class template unordered_map [unord.map]

24.5.4.3 Element access [unord.map.elem]

🔗
mapped_type& operator[](const key_type& k);
1
#
Effects: Equivalent to: return try_emplace(k).first->second;
🔗
mapped_type& operator[](key_type&& k);
2
#
Effects: Equivalent to: return try_emplace(std​::​move(k)).first->second;
🔗
template<class K> mapped_type& operator[](K&& k);
3
#
Constraints: The qualified-ids Hash​::​is_transparent and Pred​::​is_transparent are valid and denote types.
4
#
Effects: Equivalent to: return try_emplace(std​::​forward<K>(k)).first->second;
🔗
mapped_type& at(const key_type& k); const mapped_type& at(const key_type& k) const;
5
#
Returns: A reference to x.second, where x is the (unique) element whose key is equivalent to k.
6
#
Throws: An exception object of type out_of_range if no such element is present.
🔗
template<class K> mapped_type& at(const K& k); template<class K> const mapped_type& at(const K& k) const;
7
#
Constraints: The qualified-ids Hash​::​is_transparent and Pred​::​is_transparent are valid and denote types.
8
#
Preconditions: The expression find(k) is well-formed and has well-defined behavior.
9
#
Returns: A reference to find(k)->second.
10
#
Throws: An exception object of type out_of_range if find(k) == end() is true.