public static Operator_ CreateOperator(string oper)
{
Operator_ operation = null;
if (oper == "+")
{
operation = new Add();
}
else if (oper == "-")
{
operation = new Sub();
}
else if (oper == "*")
{
operation = new Mul();
}
else if (oper == "/")
{
operation = new Div();
}
return(operation);
}
static void Main(string[] args)
{
/*比较蠢的一版计算器写法，业务和界面没有分开，而且维护困难，扩展性差
* double num1, num2, result;
* string resul_t = "";
* string oper;
*
* Console.WriteLine("请输入数字1： ");
* num1 = Convert.ToDouble(Console.ReadLine());
* Console.WriteLine("字符： ");
* oper = Console.ReadLine();
* Console.WriteLine("请输入数字2： ");
* num2 = Convert.ToDouble(Console.ReadLine());
* //根据输入的运算符，进行相应的运算
* try
* {
* switch (oper)
* {
* case "+":
* result = num1 + num2;
* resul_t = result.ToString();
* break;
* case "-":
* result = num1 - num2;
* resul_t = result.ToString();
* break;
* case "*":
* result = num1 * num2;
* resul_t = result.ToString();
* break;
* case "/":
* if (num2 != 0)
* {
* result = num1 / num2;
* }
* else
* {
* resul_t = "不能为0！";
* }
*
* break;
*
*
* }
*
* Console.WriteLine("结果是： " + resul_t);
* Console.ReadKey();
* }
* catch (Exception e)
* {
* Console.WriteLine(e);
* throw;
* }*/
//第二版计算器写法，采用了简单工厂模式，分开了业务逻辑和界面逻辑，增强了可维护性，可扩展性，灵活性
Console.WriteLine("请输入数字1： ");
operation.NumA = Convert.ToDouble(Console.ReadLine());
//输入运算符
Console.WriteLine("字符： ");
string oper = Console.ReadLine();
Console.WriteLine("请输入数字2： ");
operation.NumB = Convert.ToDouble(Console.ReadLine());
double result = 0;
//根据运算符创建相应的运算类
Operator_ operation = OperationFactory.CreateOperator(oper);
//得到运算结果
result = operation.GetResult();
Console.WriteLine(result);
Console.ReadKey();
}