#define Unity2017
#define Unity2020


namespace Lesson19_预处理器指令练习
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("请输入第一个数字：");
            int a = int.Parse(Console.ReadLine());

            Console.WriteLine("请输入第二个数字：");
            int b = int.Parse(Console.ReadLine());
            Console.WriteLine(Calc(a, b));

        }
        static int Calc(int a, int b)
        {
#if Unity5
            return a + b;
#elif Unity2017
            return a*b;
#elif Unity2019
            return a-b;
#else
            return 0;
#endif
        }
    }
}