CPP

fast way to check if a number is prime C++

//O(sqrt(n))
bool isPrime(int num){
    if(num <= 1) return false;
    for(int i = 2; i <= sqrt(num); i++){
          if(num % i == 0) return false;
    }
    return true;
}

check prime cpp gfg

bool isPrime(int s){
   if(s <= 1) return false;
   if(s == 2) return true;
   for(int i = 2; i * i <= s; i++) {
       if(s % i== 0) return false;
   }
   return true;
}