diff --git a/examples/primes.cpp b/examples/primes.cpp
index a3e871a..e5ee4f0 100644
--- a/examples/primes.cpp
+++ b/examples/primes.cpp
@@ -23,6 +23,7 @@
 #include <vector>
 
 #include <math.h>
+#include <stdio.h>
 
 // searchMax defines the upper limit on primes to find.
 constexpr int searchMax = 10000000;