Prime numbers from 2 to N(O(N^2) worst case complexity)

from2tonprimes.cpp

#include <iostream>
#include <cmath>
#include <vector>

using ull = unsigned long long;

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

auto getPrime(int n) 
{
    std::vector<ull> primes;
    primes.reserve(n);
    
    for(int i = 2; i < n; i++)
    {
        if(isPrime(i))
        {
            primes.push_back(i);
        }
    }
    
    return primes;
}

int main()
{
    int primeNumber = 15331;
    auto primes = getPrime(primeNumber);
    for(const auto& item : primes)
    {
        std::cout << item << ' ';
    }
    std::cout << '\n';

    return 0;
}