diff --git a/tutorial01/README.md b/tutorial01/README.md
index 4aeb5cc..bbfc784 100644
--- a/tutorial01/README.md
+++ b/tutorial01/README.md
@@ -17,6 +17,8 @@ Following table compares a hello world program in C and CUDA side-by-side.
 **C**
 
 ``` C
+#include <stdio.h>
+
 void c_hello(){
     printf("Hello World!\n");
 }
@@ -34,12 +36,15 @@ int main() {
 **CUDA**
 
 ``` C
+#include <stdio.h>
+
 __global__ void cuda_hello(){
     printf("Hello World from GPU!\n");
 }
 
 int main() {
     cuda_hello<<<1,1>>>(); 
+    cudaDeviceSynchronize(); // force flush stdout from gpu before we exit
     return 0;
 }
 ```