diff --git a/Chapter4_StructureFromMotion/Common.cpp b/Chapter4_StructureFromMotion/Common.cpp
index cddd5c4..12530b1 100755
--- a/Chapter4_StructureFromMotion/Common.cpp
+++ b/Chapter4_StructureFromMotion/Common.cpp
@@ -17,6 +17,8 @@
 
 #ifndef WIN32
 #include <dirent.h>
+#else
+#include <windows.h>
 #endif
 
 using namespace std;