有人号称编程零基础学C#4天，用记事本1分钟写个计算器，而且信誓旦旦，这是怎么回事？ 第1页

       using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Text.RegularExpressions; using System.Threading.Tasks;  namespace CalcTest {   class Program   {     static void Main( string[] args )     {        Console.Write( "input a expression:" );       var expression = Console.ReadLine();        if ( Regex.IsMatch( expression, @"(d+)([+-*/]d+)*" ) == false )         Console.WriteLine( "invalid expression" );         Console.WriteLine( "{0}={1}", expression, new SimpleExpressionEvaluator.ExpressionEvaluator().Evaluate( expression ) );     }   } }