Solved Assignment-1 Successfully

Tavisca.Bootcamp.LanguageBasics.Exercise1/Program.cs

@@ -2,7 +2,7 @@
 
 namespace Tavisca.Bootcamp.LanguageBasics.Exercise1
 {
-    class Program
+    class FixMultiplication
     {
         static void Main(string[] args)
         {
@@ -14,16 +14,128 @@ 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)
-        {
-            // Add your code here.
-            throw new NotImplementedException();
+        public static int FindDigit(string equation)
+        {
+            /*
+                Step 1 :-
+                Divide the given equation string into 3 differnt strings, each representing a number/operand.
+                Here s1,s2 and s3 are corresponding string representation of the 3 numbers.
+            */
+
+            string s1 = "";
+            string s2 = "";
+            string s3 = "";
+            bool is_mult_sign_encountered = false;
+            bool is_equal_sign_encountered = false;
+            int question_mark = 0;
+            for (int i = 0; i < equation.Length; i++)
+            {
+                if (equation[i] == '*')
+                {
+                    is_mult_sign_encountered = true;
+                    continue;
+                }
+                if (equation[i] == '=')
+                {
+                    is_equal_sign_encountered = true;
+                    continue;
+                }
+                if (!is_mult_sign_encountered)
+                {
+                    s1 = s1 + equation[i];
+                    if (equation[i] == '?')
+                    {
+                        question_mark = 1;
+                    }
+                }
+                if (is_mult_sign_encountered && !is_equal_sign_encountered)
+                {
+                    s2 = s2 + equation[i];
+                    if (equation[i] == '?')
+                    {
+                        question_mark = 2;
+                    }
+                }
+                if (is_mult_sign_encountered && is_equal_sign_encountered)
+                {
+                    s3 = s3 + equation[i];
+                    if (equation[i] == '?')
+                    {
+                        question_mark = 3;
+                    }
+                }
+            }
+
+            /*
+                Step 2 :-
+                Determine the faulty string/number and perform the corresponding operation of the rest 
+                two string/number.
+            */
+
+            string res = "";
+            string faulty_string = "";
+            if (question_mark == 1)
+            {
+                res = Double.Parse(s3) / Double.Parse(s2) + "";
+                faulty_string = s1;
+            }
+            else if (question_mark == 2)
+            {
+                res = Double.Parse(s3) / Double.Parse(s1) + "";
+                faulty_string = s2;
+            }
+            else
+            {
+                res = Double.Parse(s1) * Double.Parse(s2) + "";
+                faulty_string = s3;
+            }
+
+            /*
+                Step 3 :-
+                if the length of the resulted string/number which is obtained by the operation of the two string/numbers
+                except the faulty string/number, differs in the length as of the string/number given in the equation,
+                gives an indication for the following cases :
+                    1.) Either the resulted number is not an integer i.e. contains decimal fraction.
+                    2.) It contains leading zeros.
+            */
+
+            if (res.Length != faulty_string.Length)
+            {
+                return -1;
+            }
+            else
+            {
+                for (int i = 0; i < res.Length; i++)
+                {
+                    /*
+                        Step 4 :-
+                        if the resultant string/number obtained mismatches with the string/number provided in the
+                        equation at any position except '?', we simply return -1
+                    */
+
+                    if (res[i] != faulty_string[i] && faulty_string[i] != '?')
+                    {
+                        return -1;
+                    }
+
+                    /*
+                        Step 5 :-
+                        if we encounter a '?', we return the corresponding digit.
+                    */
+
+                    if (res[i] != faulty_string[i] && faulty_string[i] == '?')
+                    {
+                        return Int32.Parse(res[i].ToString());
+                    }
+                }
+            }
+            return -1;
         }
     }
 }