Initial data commit

Task/CSV-data-manipulation/C-sharp/csv-data-manipulation.cs

@@ -0,0 +1,21 @@
+using System.IO;
+using System.Linq;
+
+namespace CSV_data_manipulation
+{
+    class Program
+    {
+        static void Main()
+        {
+            var input = File.ReadAllLines("test_in.csv");
+            var output = input.Select((line, i) =>
+            {
+                if (i == 0)
+                    return line + ",SUM";
+                var sum = line.Split(',').Select(int.Parse).Sum();
+                return line + "," + sum;
+            }).ToArray();
+            File.WriteAllLines("test_out.csv", output);
+        }
+    }
+}