C# 定义常量 注意：C#不能使用 #define

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication31
{
static class Constants //推荐定义常量方式
{
public const double Pi = 3.14159;
public const int SpeedOfLight = 300000; // km per sec.
}
class Program
{
static void Main(string[] args)
{
double radius = 5.3;
double area = Constants.Pi * (radius * radius);
int secsFromSun = 149476000 / Constants.SpeedOfLight; // in km

}
}
}