Prime Number in c pgm

#include 

int smalldiv (int n)

 {

  int count; 

  count = 2;

  while (count < n && n % count != 0)

 {

    count = count + 1;

  }

  return(count);

}

int main () 

{

  int n;

  cout << "Enter a natural number: ";

  cin >> n;

  if (n == smalldiv(n)) 

{

    cout << n << " is a prime number" << endl;

  }

  else 

{

    cout << n << " is not a prime number" << endl;

  }

  return(0);

}