Initial data commit

Task/Substring/C-sharp/substring-1.cs

@@ -0,0 +1,26 @@
+using System;
+namespace SubString
+{
+    class Program
+    {
+        static void Main(string[] args)
+        {
+            string s = "0123456789";
+            const int n = 3;
+            const int m = 2;
+            const char c = '3';
+            const string z = "345";
+
+            // A: starting from n characters in and of m length;
+            Console.WriteLine(s.Substring(n, m));
+            // B: starting from n characters in, up to the end of the string;
+            Console.WriteLine(s.Substring(n, s.Length - n));
+            // C: whole string minus the last character;
+            Console.WriteLine(s.Substring(0, s.Length - 1));
+            // D: starting from a known character within the string and of m length;
+            Console.WriteLine(s.Substring(s.IndexOf(c), m));
+            // E: starting from a known substring within the string and of m length.
+            Console.WriteLine(s.Substring(s.IndexOf(z), m));
+        }
+    }
+}

Task/Substring/C-sharp/substring-2.cs

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+// B: starting from n characters in, up to the end of the string;
+Console.WriteLine(s[n..]);
+// C: whole string minus the last character;
+Console.WriteLine(s[..^1]);