第一章 （1）业务与界面相分离

class Program
{
static void Main(string[] args)
{
try
{
Console.WriteLine("请输入数字A");
string numberA = Console.ReadLine();
Console.WriteLine("请输入运算符");
string operate = Console.ReadLine();
Console.WriteLine("请输入数字B");
string numberB = Console.ReadLine();

string result = Convert.ToString(GetResult(Convert.ToDouble(numberA), Convert.ToDouble(numberB), operate));
Console.WriteLine("结果为："+result);

}
catch (System.Exception ex)
{
Console.WriteLine("输入有误请重新输入");
}
}

/// <summary>
/// 实现业务逻辑与界面相分离
/// </summary>
public static double GetResult(double number1, double number2, string operate)
{
double result = 0d;
switch (operate)
{
case "+":
result = number1 + number2;
break;
case "-":
result = number1 - number2;
break;
case "*":
result = number1 * number2;
break;
case "/":
if ( number2!=0)
{
result = number1 / number2;
}
else
{
result = -1;
}
break;
}
return result;
}

}