C++ STL unordered_set get_allocator() with Examples
The get_allocator() method of unordered_set is the part of Standard Template Library(STL) of C++. This method gets the stored allocator object and returns it.
Syntax:
allocator_type get_allocator() const;
where Allocator_type is the type of allocator used by the container.
Return Value: It returns the allocator object used to construct the container.
Exceptions: In this method, an Exception is thrown if any element comparison object throws an exception.
The below program illustrates the unordered_set::get_allocator() function
Program 1:
C++
// C++ program to demonstrate // unordered_set get_allocator() #include <iostream> #include <unordered_set> // Their Library using namespace std; int main() { //'c' is object of 'unordered_set' unordered_set< int > c; //'allocator_type' is inherit in 'unordered_set' //'a' is object of 'allocator_type' //'get_allocator()' is member of 'unordered_set' unordered_set< int >::allocator_type a = c.get_allocator(); // Comparing the Allocator with Pair<int, int> cout << "Is allocator Pair<int, int> : " << boolalpha << (a == allocator<pair< int , int > >()); return 0; } |
Output
Is allocator Pair<int, int> : true
Complexity: It takes constant(O(1)) time of complexity to perform an operation.
Program 2 :
C++
// C++ program to demonstrate // unordered_set get_allocator() #include <iostream> #include <unordered_map> // Their Library using namespace std; int main( void ) { unordered_map< char , int > um; pair< const char , int >* a; a = um.get_allocator().allocate(8); cout << "Allocated size = " << sizeof (*a) * 8 << endl; return 0; } |
Output
Allocated size = 64
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