How to Find the Size of a Set in C++?

In C++, sets are STL containers that store unique elements of the same type in a sorted manner. No duplicate elements are allowed in the sets, as the value of every element in a set is unique. In this article, we will learn how we can find the size of a set container in C++.

Example:

Input:
mySet={1,2,3,4,5,6,7,8}

Output:
The size of mySet is: 8

Find the Size of a Set in C++

The size of the set container refers to the number of elements currently present in it. The std::set container provides a member function named std::set::size() which returns the size of the set or the number of elements in the set.

Syntax of std::set::size()

set_name.size()

C++ Program to Find the Size of a Set

C++

// C++ program to Find the Size of a Set in C++
#include <iostream>
#include <set>

using namespace std;

int main()
{
    // initialize a set
    set<int> s = { 1, 2, 3, 4, 5, 6, 7, 8 };

    // Find the size of the set using the size() function
    cout << "Size of the set is : " << s.size() << endl;

    return 0;
}

Output

Size of the set is : 8

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