cpp timer

#include <iostream>
#include <chrono>
#include <vector>
using namespace std;

class Timer
{
public:
    Timer() : seconds(0) {}
    ~Timer() {}

    void start() { s = std::chrono::system_clock::now(); }
    void stop()
    {
        e = std::chrono::system_clock::now();
        std::chrono::duration<double> diff = (e - s);
        seconds = diff.count();
    }

    double elapsedSeconds() { return seconds; }

private:
    std::chrono::time_point<std::chrono::system_clock> s, e;
    double seconds;
};

int main(void)
{
    Timer timer;
    timer.start();
    timer.stop();
    cout << timer.elapsedSeconds() << endl;

    return 0;
}