Initial data commit

Task/Caesar-cipher/D/caesar-cipher-1.d

@@ -0,0 +1,22 @@
+import std.stdio, std.traits;
+
+S rot(S)(in S s, in int key) pure nothrow @safe
+if (isSomeString!S) {
+    auto res = s.dup;
+
+    foreach (immutable i, ref c; res) {
+        if ('a' <= c && c <= 'z')
+            c = ((c - 'a' + key) % 26 + 'a');
+        else if ('A' <= c && c <= 'Z')
+            c = ((c - 'A' + key) % 26 + 'A');
+    }
+    return res;
+}
+
+void main() @safe {
+    enum key = 3;
+    immutable txt = "The five boxing wizards jump quickly";
+    writeln("Original:  ", txt);
+    writeln("Encrypted: ", txt.rot(key));
+    writeln("Decrypted: ", txt.rot(key).rot(26 - key));
+}