what does count function do in hashmap

// C++ program to illustrate 
// the map::count() function 
#include <bits/stdc++.h> 
using namespace std; 
  
int main() 
{ 
  
    // initialize container 
    map<int, int> mp; 
  
    // insert elements in random order 
    mp.insert({ 2, 30 }); 
    mp.insert({ 1, 40 }); 
    mp.insert({ 3, 60 }); 
    mp.insert({ 4, 20 }); 
    mp.insert({ 5, 50 }); 
  
    // checks if key 1 is present or not 
    if (mp.count(1)) 
        cout << "The key 1 is present\n"; 
    else
        cout << "The key 1 is not present\n"; 
  
    // checks if key 100 is present or not 
    if (mp.count(100)) 
        cout << "The key 100 is present\n"; 
    else
        cout << "The key 100 is not present\n"; 
  
    return 0; 
} 
Output:
The key 1 is present
The key 100 is not present