diff --git a/tutorials/mpi-reduce-and-allreduce/code/reduce_stddev.c b/tutorials/mpi-reduce-and-allreduce/code/reduce_stddev.c
index 4560d37..72d2838 100644
--- a/tutorials/mpi-reduce-and-allreduce/code/reduce_stddev.c
+++ b/tutorials/mpi-reduce-and-allreduce/code/reduce_stddev.c
@@ -12,6 +12,7 @@
 #include <mpi.h>
 #include <math.h>
 #include <assert.h>
+#include <time.h>
 
 // Creates an array of random numbers. Each number has a value from 0 - 1
 float *create_rand_nums(int num_elements) {