std::set<Key,Compare,Allocator>::empty

Checks if the container has no elements, i.e. whether begin() == end().

# Declarations

bool empty() const;

(noexcept since C++11)

# Return value

true if the container is empty, false otherwise.

# Example

#include <iostream>
#include <set>
 
int main()
{
    std::set<int> numbers;
    std::cout << std::boolalpha;
    std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';
 
    numbers.insert(42);
    numbers.insert(19937);
    std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n';
}

# See also