1diff --git a/Utils/Logger.cpp b/Utils/Logger.cpp
2index 747cd63..e3efdf1 100644
3--- a/Utils/Logger.cpp
4+++ b/Utils/Logger.cpp
5@@ -29,7 +29,7 @@ Logger::Logger(char* tracepath) {
6 trace = fopen(tracepath, "w");
7
8 // dot file is not used, set null as default value
9- dot = '\0';
10+ dot = nullptr;
11 //dot = fopen("gcKons.dot", "w");
12 //fprintf(dot,"digraph G {\n");
13 }