Data commit

Task/Roman-numerals-Decode/C-sharp/roman-numerals-decode.cs

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+using System;
+using System.Collections.Generic;
+
+namespace Roman
+{
+    internal class Program
+    {
+        private static void Main(string[] args)
+        {
+            // Decode and print the numerals.
+            Console.WriteLine("{0}: {1}", "MCMXC", Decode("MCMXC"));
+            Console.WriteLine("{0}: {1}", "MMVIII", Decode("MMVIII"));
+            Console.WriteLine("{0}: {1}", "MDCLXVI", Decode("MDCLXVI"));
+        }
+
+        // Dictionary to hold our numerals and their values.
+        private static readonly Dictionary<char, int> RomanDictionary = new Dictionary<char, int>
+                                                                            {
+                                                                                {'I', 1},
+                                                                                {'V', 5},
+                                                                                {'X', 10},
+                                                                                {'L', 50},
+                                                                                {'C', 100},
+                                                                                {'D', 500},
+                                                                                {'M', 1000}
+                                                                            };
+
+        private static int Decode(string roman)
+        {
+            /* Make the input string upper-case,
+             * because the dictionary doesn't support lower-case characters. */
+            roman = roman.ToUpper();
+
+            /* total = the current total value that will be returned.
+             * minus = value to subtract from next numeral. */
+            int total = 0, minus = 0;
+
+            for (int i = 0; i < roman.Length; i++) // Iterate through characters.
+            {
+                // Get the value for the current numeral. Takes subtraction into account.
+                int thisNumeral = RomanDictionary[roman[i]] - minus;
+
+                /* Checks if this is the last character in the string, or if the current numeral
+                 * is greater than or equal to the next numeral. If so, we will reset our minus
+                 * variable and add the current numeral to the total value. Otherwise, we will
+                 * subtract the current numeral from the next numeral, and continue. */
+                if (i >= roman.Length - 1 ||
+                    thisNumeral + minus >= RomanDictionary[roman[i + 1]])
+                {
+                    total += thisNumeral;
+                    minus = 0;
+                }
+                else
+                {
+                    minus = thisNumeral;
+                }
+            }
+
+            return total; // Return the total.
+        }
+    }
+}