How to Check if a Set is Empty in C++?

In C++, a set is an associative container that stores unique elements in a sorted order. In this article, we'll explore different approaches to check if a set is empty in C++ STL.

Check if a Set is Empty or Not in C++

To check if a std::set is empty in C++, we can use the std::set::empty() function. This function returns a boolean value indicating whether the set is empty.

C++ Program to Check if a Set is Empty

Set1 is empty.
Set2 is not empty.

Time Complexity: O(1)
Auxiliary Space: O(1)

The set container in C++ STL provides an size() member function that returns the size (or number of elements) of the set. We can also check is a set is empty or not using size() function in C++ because if the size is 0, then the set is empty otherwise not.