set count() function in C++ STL
The set::count() is a built-in function in C++ STL which returns the number of times an element occurs in the set. It can only return 1 or 0 as the set container contains unique elements only.
Syntax:
set_name.count(element)
Parameters: The function accepts one mandatory parameter element which specifies the element whose count is to be returned.
Return Value: The function returns 1 or 0 as the set contains unique elements only. It returns 1 if the value is present in the set container. It returns 0 if it is not present in the container.
Time Complexity : Time Complexity for count function is O(log N) where N is the number of elements present in the set
Difference between count and find function in a set is count returns 0 or 1 depending upon whether element is not present or present respectively whereas find function returns a iterator pointing to the value if present else next to the last value in the set.
Below is the illustration of the above function.
CPP
// CPP program to demonstrate the// set::count() function#include <bits/stdc++.h>using namespace std;int main(){ int arr[] = { 14, 12, 15, 11, 10 }; // initializes the set from an array set<int> s(arr, arr + 5); // check if 11 is present or not if (s.count(11)) cout << "11 is present in the set\n"; else cout << "11 is not present in the set\n"; // checks if 18 is present or not if (s.count(18)) cout << "18 is present in the set\n"; else cout << "18 is not present in the set\n"; return 0;} |
11 is present in the set 18 is not present in the set
