chore: Add course material

397/Ex11/Timer.h

@@ -0,0 +1,27 @@
+// ======================================================
+//
+// A general-purpose countdown timer
+// To use this class, specialize it
+// and override tick()
+//
+// ======================================================
+
+#ifndef TIMER_H
+#define TIMER_H
+
+class Timer {
+  public:
+    Timer();
+
+    void timeoutRequest(int seconds);
+
+    virtual void tick() = 0;
+
+  protected:
+    bool isExpired();
+
+  private:
+    int timeToGo;
+};
+
+#endif