Merged from development to master.

Tavisca.Bootcamp.LanguageBasics.Exercise1/FixMultiplication.cs

@@ -0,0 +1,78 @@
+using System;
+
+namespace Tavisca.Bootcamp.LanguageBasics.Exercise1
+{
+    public class FixMultiplication
+    {
+       public static int FindDigit (string equation) {
+           // Find Indexes of special characters in String.
+            var m = equation.IndexOf("*");
+            var e = equation.IndexOf("=");
+            var q = equation.IndexOf("?");
+
+            // Split string in expression and result
+            string[] result = equation.Split("=");
+
+            // Split expression to extract numbers.
+            string[] num = result[0].Split("*");
+
+            // if ? is after =
+            if (e < q) {
+                // Convert numbers from string to integer.
+                var n1 = Convert.ToInt32(num[0]);
+                var n2 = Convert.ToInt32(num[1]);
+                var res = n1 * n2 + "";
+                // return an integer on same index as ?, 
+                // - 48 to convert to actual value from ASCII
+                return Convert.ToInt32(res[q-e-1]) - 48;
+            } 
+            // ? in expression part i.e before =
+            else {
+                // ? in num1
+                if (m > q) {
+                    // Get res and n2 as integers.
+                    var res = Convert.ToInt32(result[1]);
+                    var n2 = Convert.ToInt32(num[1]);
+                    // If integral multiplication is possible
+                    if (res % n2 == 0) {
+                        // Evaluate n1 and convert to string.
+                        var n1 = res / n2 + "";
+                        // If ? is at ones place and it has value zero 
+                        if (n1.Length < num[0].Length) {
+                            return -1;
+                        } 
+                        // If ? is not at ones place or it has non-zero value.
+                        else {
+                            // - 48 to convert to actual value from ASCII
+                            return Convert.ToInt32(n1[q]) - 48;
+                        }
+                    } 
+                    // Integral multiplication impossible
+                    else {
+                        return -1;
+                    }
+                } 
+                // ? in num2
+                else {
+                    // Get res and n1 as integer
+                    var res = Convert.ToInt32(result[1]);
+                    var n1 = Convert.ToInt32(num[0]);
+                    // If integral multiplication possible
+                    if (res % n1 == 0) {
+                        // Evaluate n2 and convert to string
+                        var n2 = res / n1 + "";
+                        // zero at ones place
+                        if (n2.Length < num[1].Length) {
+                            return -1;
+                        } else {
+                            // - 48 to convert to actual value from ASCII
+                            return Convert.ToInt32(n2[q-m-1]) - 48;
+                        }
+                    } else {
+                        return -1;
+                    }
+                }
+            }
+       }
+    }
+}

Tavisca.Bootcamp.LanguageBasics.Exercise1/Program.cs

@@ -14,16 +14,17 @@ static void Main(string[] args)
             Console.ReadKey(true);
         }
 
-        private static void Test(string args, int expected)
-        {
+        private static void Test(string args, int expected)
+        {
             var result = FindDigit(args).Equals(expected) ? "PASS" : "FAIL";
-            Console.WriteLine($"{args} : {result}");
+            Console.WriteLine($"{args} : {result}");
         }
 
-        public static int FindDigit(string equation)
-        {
+        public static int FindDigit(string equation)
+        {
             // Add your code here.
-            throw new NotImplementedException();
+            // throw new NotImplementedException();
+            return FixMultiplication.FindDigit(equation);
         }
     }
 }