Data commit

Task/CUSIP/C-sharp/cusip.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+
+namespace CUSIP {
+    class Program {
+        static bool IsCusip(string s) {
+            if (s.Length != 9) return false;
+            int sum = 0;
+            for (int i = 0; i <= 7; i++) {
+                char c = s[i];
+
+                int v;
+                if (c >= '0' && c <= '9') {
+                    v = c - 48;
+                }
+                else if (c >= 'A' && c <= 'Z') {
+                    v = c - 55;  // lower case letters apparently invalid
+                }
+                else if (c == '*') {
+                    v = 36;
+                }
+                else if (c == '#') {
+                    v = 38;
+                }
+                else {
+                    return false;
+                }
+                if (i % 2 == 1) v *= 2;  // check if odd as using 0-based indexing
+                sum += v / 10 + v % 10;
+            }
+            return s[8] - 48 == (10 - (sum % 10)) % 10;
+        }
+
+        static void Main(string[] args) {
+            List<string> candidates = new List<string>() {
+                "037833100",
+                "17275R102",
+                "38259P508",
+                "594918104",
+                "68389X106",
+                "68389X105"
+            };
+            foreach (var candidate in candidates) {
+                Console.WriteLine("{0} -> {1}", candidate, IsCusip(candidate) ? "correct" : "incorrect");
+            }
+        }
+    }
+}