static void Main(string[] args)
{
StopWatch stopWatch = new StopWatch();
while (true)
{
Console.WriteLine("1-start::2-stop::3-quit");
var inputNum = Convert.ToInt32(Console.ReadLine());
if (inputNum == 1)
{
stopWatch.Start();
}
else if (inputNum == 2)
{
stopWatch.Stop();
stopWatch.Calculate();
}
else if (inputNum == 3)
{
Environment.Exit(0);
}
else
{
throw new InvalidOperationException("Invalid input");
}
}
}
