The multimap clear() function is an inbuilt function in C++ STL which is used to remove all elements from the multimap container (which are destroyed), leaving the container with a size of 0.
Syntax :
mymultimap_name.clear()
Parameters: This function does not take any arguments.
Return Value: This function does not returns anything. The return type of the function is void. It just empties the whole container.
Below program illustrate the multimap::clear() function in C++:
C++
// CPP program to illustrate the // multimap::clear() function #include <cstring> #include <iostream> #include <map> using namespace std; int main() { // Creating multimap of string and int multimap<string, int > mymultimap; // Inserting 3 Items with their value // using insert function mymultimap.insert(pair<string, int >( "Item1" , 10)); mymultimap.insert(pair<string, int >( "Item2" , 20)); mymultimap.insert(pair<string, int >( "Item3" , 30)); cout << "Size of the multimap before using " << "clear function : " ; cout << mymultimap.size() << '\n' ; // Removing all the elements // present in the multimap mymultimap.clear(); cout << "Size of the multimap after using" << " clear function : " ; cout << mymultimap.size() << '\n' ; return 0; } |
Size of the multimap before using clear function : 3 Size of the multimap after using clear function : 0
Time Complexity: O(N), where N is the total number of elements in multimap.
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