diff --git a/cpp/3_CUDA_Features/cdpQuadtree/cdpQuadtree.cu b/cpp/3_CUDA_Features/cdpQuadtree/cdpQuadtree.cu
index 804d25502..cb099058f 100644
--- a/cpp/3_CUDA_Features/cdpQuadtree/cdpQuadtree.cu
+++ b/cpp/3_CUDA_Features/cdpQuadtree/cdpQuadtree.cu
@@ -26,6 +26,7 @@
  */
 
 #include <cooperative_groups.h>
+#include <iostream>
 #include <thrust/device_vector.h>
 #include <thrust/host_vector.h>
 #include <thrust/random.h>