is_divisible_by_1_to_20.cpp

#include <iostream>

using namespace std;

struct measure {
    template<typename F, typename ...Args>
    static void execution(F func, Args&&... args) {
        auto start = chrono::system_clock::now();
        func(forward<Args>(args)...);
        auto duration = chrono::system_clock::now() - start;
        cout << "Elapsed: " << duration.count() / 1000 << "ms" << endl;
    }
};

bool isDivisibleBy1To20(long n) {
    if (n % 20 != 0) {
        return 0;
    }
    for (int i = 11; i <= 20; i++) {
        if (n % i != 0) {
            return 0;
        }
    }
    return 1;
}

int main() {
    long x = 1;

    measure::execution([&x]() {
        while (x++) {
            if (isDivisibleBy1To20(x)) {
                cout << "Number is " << x << endl;
                break;
            }
        }
    });

    return 0;
}