prime.cpp

#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
#include "doctest.h"

using ll = long long;
bool isPrime(ll n)
{
    if (n == 1) return false;

    auto ub = std::sqrt(n);
    for (int i = 2; i <= ub; i += 1) {
        if ((n % i) == 0) return false;
    }
  
    return true;
}

TEST_CASE("Check primes") {
    for (ll i : {2, 3, 5, 7, 1117, 7639}) {
        CHECK(isPrime(i));
    }

    for (ll i : {1, 4, 6, 9, 1118, 7631}) {
        CHECK_FALSE(isPrime(i));
    }
}