Add Duplicate Character Counter in Wren (#4499)

Author: Kaamkiya

archive/w/wren/duplicate-character-counter.wren

@@ -0,0 +1,44 @@
+import "os" for Process
+
+var args = Process.arguments
+
+if (args.count != 1 || args[0] == "") {
+  System.print("Usage: please provide a string")
+  Fiber.suspend()
+}
+
+var chars = {}
+var order = []
+var dupes = false
+
+for (c in args[0]) {
+  if (chars[c] == null) {
+    chars[c] = 0
+  } else {
+    dupes = true
+  }
+
+  chars[c] = chars[c] + 1
+
+  var contains = false
+  for (a in order) {
+    if (c == a) {
+      contains = true
+      break
+    }
+  }
+
+  if (!contains) {
+    order.add(c)
+  }
+}
+
+if (dupes) {
+  for (c in order) {
+    if (chars[c] > 1) {
+      System.print(c + ": " + chars[c].toString)
+    }
+  }
+} else {
+  System.print("No duplicate characters")
+}