diff --git a/src/gui.cpp b/src/gui.cpp
index aa03e21..93b761f 100644
--- a/src/gui.cpp
+++ b/src/gui.cpp
@@ -125,10 +125,10 @@ static void TryLoad(const char *filename)
 
 Gui *Gui::Open()
 {
-	if (g_builder == NULL) {
+	if (!g_builder) {
 		const char * const *dirs = g_get_system_data_dirs();
 
-		while (*dirs != NULL && g_builder == NULL) {
+		while (*dirs != NULL && !g_builder) {
 			std::string path = *dirs;
 			path = Glib::build_filename(path, PACKAGE_NAME);
 			path = Glib::build_filename(path, "jsweeper.ui");
@@ -138,9 +138,9 @@ Gui *Gui::Open()
 			dirs++;
 		}
 
-		if (g_builder == NULL) TryLoad("jsweeper.ui");
+		if (!g_builder) TryLoad("jsweeper.ui");
 
-		if (g_builder == NULL) {
+		if (!g_builder) {
 			std::cerr << "Failed to load jsweeper.ui!" << std::endl;
 			exit(-1);
 		}