The C++ function std::unordered_multimap::insert() extends unordered_multimap by inserting new element from initializer list. This function increases container size by one.
Following is the declaration for std::unordered_multimap::insert() function form std::unordered_map() header.
void insert(initializer_list<value_type> il);
il − Initializer list.
None
Constant i.e. O(1) in average case.
Linear i.e. O(n) in worst case.
The following example shows the usage of std::unordered_multimap::insert() function.
#include <iostream> #include <unordered_map> using namespace std; int main(void) { unordered_multimap<char, int> umm = { {'a', 1}, {'b', 2}, {'c', 3}, }; umm.insert({{'d', 4}, {'e', 5}}); cout << "Unordered multimap contains following elements" << endl; for (auto it = umm.begin(); it != umm.end(); ++it) cout << it->first << " = " << it->second << endl; return 0; }
Let us compile and run the above program, this will produce the following result −
Unordered multimap contains following elements e = 5 d = 4 c = 3 a = 1 b = 2