C# 静态类和静态成员

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

namespace ConsoleApplication29
{
class Program
{
//非静态类的静态成员：无论创建多少个对象，静态成员只有一个副本
static void Main()
{
Console.WriteLine("Please select the convertor direction");
Console.WriteLine("1. From Celsius to Fahrenheit.");
Console.WriteLine("2. From Fahrenheit to Celsius.");
Console.Write(":");

string selection = Console.ReadLine();
double F, C = 0;

switch (selection)
{
case "1":
Console.Write("Please enter the Celsius temperature: ");
F = TemperatureConverter.CelsiusToFahrenheit(Console.ReadLine());
Console.WriteLine("Temperature in Fahrenheit: {0:F2}", F);
break;

case "2":
Console.Write("Please enter the Fahrenheit temperature: ");
C = TemperatureConverter.FahrenheitToCelsius(Console.ReadLine());
Console.WriteLine("Temperature in Celsius: {0:F2}", C);
break;

default:
Console.WriteLine("Please select a convertor.");
break;
}

// Keep the console window open in debug mode.
Console.WriteLine("Press any key to exit.");
Console.ReadKey();
}

}
public static class TemperatureConverter
{
public static double CelsiusToFahrenheit(string temperatureCelsius)
{
// Convert argument to double for calculations.
double celsius = Double.Parse(temperatureCelsius);

// Convert Celsius to Fahrenheit.
double fahrenheit = (celsius * 9 / 5) + 32;

return fahrenheit;
}

public static double FahrenheitToCelsius(string temperatureFahrenheit)
{
// Convert argument to double for calculations.
double fahrenheit = Double.Parse(temperatureFahrenheit);

// Convert Fahrenheit to Celsius.
double celsius = (fahrenheit - 32) * 5 / 9;

return celsius;
}
}

}