計算機小程式

CalculatorByCodeDom.cs

using System;
using System.CodeDom;
using System.CodeDom.Compiler;
using Microsoft.CSharp;

namespace Calculator
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            while (true)
            {
                Console.WriteLine("請輸入你的算式，如要離開請按【Q】");
                string input = Console.ReadLine();
                if (input.Length == 0) continue;
                if (input.ToUpper() == "Q") break;

                input = input.Replace("--", "+").Replace("+-", "-").Replace("-+", "-");
                string errorMsg;
                double d = ConstructCs(input, out errorMsg);
                if (errorMsg.Length > 0) Console.WriteLine(errorMsg);
                else Console.WriteLine(string.Format("答案 = {0}\n", d));
            }
        }

        private static double ConstructCs(string input, out string errorMsg)
        {
            string code = string.Format(
@"using System;
namespace Frank
{{
  public class Calculator
  {{
    public double CalcIt()
    {{
       double d = {0}f;
       return d;
    }}
  }}
}}", input);

            CSharpCodeProvider comp = new CSharpCodeProvider();
            CompilerParameters cp = new CompilerParameters();
            cp.ReferencedAssemblies.Add("system.dll");

            cp.GenerateExecutable = false;
            cp.GenerateInMemory = true;
            CompilerResults cr = comp.CompileAssemblyFromSource(cp, code);
            if (cr.Errors.HasErrors)
            {
                errorMsg = "輸入格式格式有誤\n";
                return -1;
            }

            dynamic c = cr.CompiledAssembly.CreateInstance("Frank.Calculator");
            errorMsg = string.Empty;
            return c.CalcIt();
        }
    }
}