C#-Chart06

这是课程6中更改后的，原文显示的有些看不懂

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

//using static System.Console;
//using static System.Convert;

namespace Ch06Ex05
{
class Program
{
delegate double ProcessDelegate(double param1, double param2);

/******

原文是：

static double Multiply(double param1, double param2) => param1 * param2;
static double Divide(double param1, double param2) => param1 / param2;

注：这个编译报错VS2013

*********/

修改后的是：

static double Multiply(double param1, double param2)
{
return param1 * param2;
}
static double Divide(double param1, double param2)
{
return param1 / param2;
}

这个正常，请问是什么原因呢？

static void Main(string[] args)
{
ProcessDelegate process;
Console.WriteLine("Enter 2 numbers separated with a comma:");
string input = Console.ReadLine();
int commaPos = input.IndexOf(',');
double param1 = Convert.ToDouble(input.Substring(0, commaPos));
double param2 = Convert.ToDouble(input.Substring(commaPos + 1,
input.Length - commaPos - 1));
Console.WriteLine("Enter M to multiply or D to divide:");
input = Console.ReadLine();
if (input == "M")
process = new ProcessDelegate(Multiply);
else
process = new ProcessDelegate(Divide);
Console.WriteLine("Result: {0}", process(param1, param2));
Console.ReadKey();
}
}
}