set find() Function in C++ STL
Last Updated :
11 Jul, 2025
Improve
The std::set::find() is a built-in function in C++ STL that is used to find an element in the set container. It is a member function of std::set container so we can use it directly with any set object.
Syntax
set_name.find(key)
Parameters
- key: The element which we have to find.
Return Value
- If the element is found, it returns an iterator to its position in the set.
- If the element is not found, then it returns the iterator to the end.
Finding elements in a set is straightforward with the find() function.
Example of set::find()
// C++ program to demonstrate the use of
// set::find() function
#include <bits/stdc++.h>
using namespace std;
int main() {
// Create a set
set<int> st;
st.insert(11);
st.insert(14);
st.insert(2);
st.insert(15);
st.insert(3);
// key1 find (exist in the set)
int key1 = 3;
// key2 find (does not exist in the set)
int key2 = 1;
// Check if key1 is found
if (st.find(key1) != st.end())
cout << "Key '" << key1 << "' found" << endl;
// Element not present
else
cout << "Key '" << key1 << "' not found!" << endl;
// Check if key2 is found
if (st.find(key2) != st.end())
cout << "Key '" << key2 << "' found" << endl;
// key2 not found
else
cout << "Key '" << key2 << "' not found!" << endl;
return 0;
}
// C++ program to demonstrate the use of// set::find() functionusing namespace std;int main() { // Create a set set<int> st; st.insert(11); st.insert(14); st.insert(2); st.insert(15); st.insert(3); // key1 find (exist in the set) int key1 = 3; // key2 find (does not exist in the set) int key2 = 1; // Check if key1 is found if (st.find(key1) != st.end()) cout << "Key '" << key1 << "' found" << endl; // Element not present else cout << "Key '" << key1 << "' not found!" << endl; // Check if key2 is found if (st.find(key2) != st.end()) cout << "Key '" << key2 << "' found" << endl; // key2 not found else cout << "Key '" << key2 << "' not found!" << endl; return 0;}Output
Key '3' found Key '1' not found!
Complexity Analysis of set::find()
- Time Complexity: O(log n), where n is the number of elements.
- Space Complexity: O(1)
