diff --git a/X11Exception.h b/X11Exception.h
index c0468bf..3585570 100644
--- a/X11Exception.h
+++ b/X11Exception.h
@@ -13,7 +13,7 @@ class X11Exception : public std::exception
 {
 public:
     X11Exception() : _reason("unknown") {}
-    X11Exception(const std::string& what) : _reason(what) {}
+    explicit X11Exception(const std::string& what) : _reason(what) {}
     virtual ~X11Exception() throw () {};
     virtual const char* what() const throw () { return _reason.c_str(); }
 
@@ -21,9 +21,8 @@ private:
     std::string _reason;
 };
 
-#endif // GAMEEXCEPTION_H_FE39A315_6827_447B_AE62_5FA2C3FD391F
+#endif // X11EXCEPTION_H_FE39A315_6827_447B_AE62_5FA2C3FD391F
 
 // Local Variables:
 // mode: c++
 // End:
-
diff --git a/wrapper.cpp b/wrapper.cpp
index bc3a46d..93fc636 100644
--- a/wrapper.cpp
+++ b/wrapper.cpp
@@ -59,7 +59,7 @@ bool print_status(XKeyboard& xkb, string format) {
     stringstream r;     // resulting string
 
     for (size_t i = 0; i < format.length(); ++i) {
-        if (format[i] == '%' && i < format.length()-1) {
+        if (i < format.length()-2 && format[i] == '%') {
             switch (format[i+1]) {
                 case 'c':
                     r << xkb.currentGroupNum();
@@ -180,8 +180,8 @@ int main(int argc, char* argv[])
             }
         }
     }
-    catch (exception e) {
-        cerr << e.what() << endl;
+    catch (const exception *e) {
+        cerr << e->what() << endl;
         return EXIT_FAILURE;
     }
     return EXIT_SUCCESS;