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.

Below is the illustration of the above function.

// 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; 
} 

Output:

11 is present in the set
18 is not present in the set

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