#include <iostream>
#include <cmath>

bool isPrime(int number) {
    if (number <= 1) {
        return false; // 0 and 1 are not prime numbers
    }
    if (number == 2) {
        return true; // 2 is a prime number
    }
    if (number % 2 == 0) {
        return false; // Even numbers greater than 2 are not prime
    }
    for (int i = 3; i <= std::sqrt(number); i += 2) {
        if (number % i == 0) {
            return false; // Divisible by a number other than 1 and itself
        }
    }
    return true;
}

int main() {
    int number;
    std::cout << "Enter a number: ";
    std::cin >> number;

    if (isPrime(number)) {
        std::cout << number << " is a prime number.\n";
    } else {
        std::cout << number << " is not a prime number.\n";
    }

    return 0;
}

Bu yerda tub sonni aniqlaydigan sodda kod berilgan. 
Bu kodni har tomonlama optimizatsiya qilsa bo'ladi!
Fikringizni izohlarda qoldiring

#include <iostream>
#include <vector>

void sieveOfEratosthenes(int n) {
    std::vector<bool> primes(n); // Using a vector to store prime numbers
    for (int i = 0; i < n; i++) { 
        primes[i] = true; // Initialize all numbers as prime
    }
    
    primes[0] = primes[1] = false; // 0 and 1 are not prime numbers

    for (int p = 2; p < n; p++) { // Iterating up to n instead of sqrt(n)
        if (primes[p]) { // If the number is still marked as prime
            for (int i = p * p; i < n; i += p) { // Start marking multiples from p * p
                primes[i] = false; // Mark multiples as non-prime
            }
        }
    }

    // Print prime numbers
    std::cout << "Prime numbers up to " << n << ": ";
    for (int i = 2; i < n; i++) {
        if (primes[i]) {
            std::cout << i << " ";
        }
    }
    std::cout << std::endl;
}

int main() {
    int n = 50; // Fixed value for testing
    sieveOfEratosthenes(n);
    return 0;
}

#include <iostream>
#include <cmath>

constexpr bool isPrime(int number) {
    if (number <= 1) return false;
    if (number <= 3) return true; 
    if (number % 2 == 0 || number % 3 == 0) return false; 

    for (int i = 5; i * i <= number; i += 6) {
        if (number % i == 0 || number % (i + 2) == 0) {
            return false;
        }
    }
    return true;
}

int main() {
    int number;
    std::cin >> number;
    for(int i = 1; i <= number; i++){
        if(isPrime(i))
            std::cout << i << " ";
    }
    return 0;
}

int main() {
    constexpr int number = 15555;//bu ham compile timeda hisoblanadi
    if(isPrime(number))
       std::cout <<"Tub" << "";
    return 0;
}

  /**
       *  @brief  Builds a %vector from an initializer list.
       *  @param  __l  An initializer_list.
       *  @param  __a  An allocator.
       *
       *  Create a %vector consisting of copies of the elements in the
       *  initializer_list @a __l.
       *
       *  This will call the element type's copy constructor N times
       *  (where N is @a __l.size()) and do no memory reallocation.
       */
      _GLIBCXX20_CONSTEXPR
      vector(initializer_list<value_type> __l,
       const allocator_type& __a = allocator_type())
      : _Base(__a)
      {
  _M_range_initialize(__l.begin(), __l.end(),
          random_access_iterator_tag());
      }