--- a/tools/power/rapl.cpp
+++ b/tools/power/rapl.cpp
@@ -714,18 +714,18 @@ Finish()
   //
   // where |x| is the sum variable, |m| is the mean, and |n| is the
   // population size.
   //
   // This is different from the *sample* standard deviation, which divides by
   // |n - 1|, and would be appropriate if we were using a random sample of a
   // larger population.
   double sumOfSquaredDeviations = 0;
-  for (auto iter = gTotals_W.begin(); iter != gTotals_W.end(); ++iter) {
-    double deviation = (*iter - mean);
+  for (double & iter : gTotals_W) {
+    double deviation = (iter - mean);
     sumOfSquaredDeviations += deviation * deviation;
   }
   double popStdDev = sqrt(sumOfSquaredDeviations / n);
 
   // Sort so that percentiles can be determined. We use the "Nearest Rank"
   // method of determining percentiles, which is simplest to compute and which
   // chooses values from those that appear in the input set.
   std::sort(gTotals_W.begin(), gTotals_W.end());