CDE

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

@@ -0,0 +1,21 @@
+import std.stdio, std.traits;
+
+pure S rot(S)(in S s, in int key) if (isSomeString!S) {
+    auto res = s.dup;
+
+    foreach (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 cast(S) res;
+}
+
+void main() {
+    int key = 3;
+    auto txt = "The five boxing wizards jump quickly";
+    writeln("Original:  ", txt);
+    writeln("Encrypted: ", txt.rot(key));
+    writeln("Decrypted: ", txt.rot(key).rot(26 - key));
+}

Task/Caesar-cipher/D/caesar-cipher-2.d

@@ -0,0 +1,20 @@
+import std.stdio, std.ascii;
+
+void inplaceRot(char[] txt, in int key) pure nothrow {
+    foreach (ref c; txt) {
+        if (isLower(c))
+            c = (c - 'a' + key) % 26 + 'a';
+        else if (isUpper(c))
+            c = (c - 'A' + key) % 26 + 'A';
+    }
+}
+
+void main() {
+    enum key = 3;
+    auto txt = "The five boxing wizards jump quickly".dup;
+    writeln("Original:  ", txt);
+    txt.inplaceRot(key);
+    writeln("Encrypted: ", txt);
+    txt.inplaceRot(26 - key);
+    writeln("Decrypted: ", txt);
+}