task3

Eval/EvalProgram.cs

@@ -1,14 +1,43 @@
 using System;
+using System.Data;
+using System.Globalization;
+using System.Linq.Expressions;
+using NUnit.Framework;
 
 namespace EvalTask
 {
 	class EvalProgram
 	{
-		static void Main(string[] args)
+        static double Evaluate(string expression)
+        {
+            var loDataTable = new DataTable();
+            var loDataColumn = new DataColumn("Eval", typeof(double), expression);
+            loDataTable.Columns.Add(loDataColumn);
+            loDataTable.Rows.Add(0);
+            return (double)(loDataTable.Rows[0]["Eval"]);
+        }
+        static string EvalExpression(string exprStr)
+        {
+            return Evaluate(exprStr).ToString(CultureInfo.InvariantCulture);
+
+        }
+        static void Main(string[] args)
 		{
 			string input = Console.In.ReadToEnd();
 			string output = "TODO";
 			Console.WriteLine(output);
 		}
+
+	    [Test]
+	    public void TestEvaluator()
+	    {
+	        Assert.AreEqual("5.8", EvalExpression("2.8+3"));
+	    }
+
+	    [Test]
+	    public void Unary_Minus_Test()
+	    {
+            Assert.AreEqual("0.2", EvalExpression("-2.8+3"));
+        }
 	}
 }