diff --git a/src/CalcManager/CEngine/calc.cpp b/src/CalcManager/CEngine/calc.cpp
index d79fa3f0..7a7cfa82 100644
--- a/src/CalcManager/CEngine/calc.cpp
+++ b/src/CalcManager/CEngine/calc.cpp
@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-#include <assert.h>
+#include <cassert>
 #include "Header Files/CalcEngine.h"
 #include "CalculatorResource.h"
 
diff --git a/src/CalcManager/CalculatorHistory.cpp b/src/CalcManager/CalculatorHistory.cpp
index b1779835..935ea8da 100644
--- a/src/CalcManager/CalculatorHistory.cpp
+++ b/src/CalcManager/CalculatorHistory.cpp
@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-#include <assert.h>
+#include <cassert>
 #include "CalculatorHistory.h"
 
 using namespace std;
diff --git a/src/CalcManager/UnitConverter.cpp b/src/CalcManager/UnitConverter.cpp
index 06112e27..4a4aa3a9 100644
--- a/src/CalcManager/UnitConverter.cpp
+++ b/src/CalcManager/UnitConverter.cpp
@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
-#include <assert.h>
+#include <cassert>
 #include <sstream>
 #include "Command.h"
 #include "UnitConverter.h"
diff --git a/src/CalcManager/pch.h b/src/CalcManager/pch.h
index 7c930491..2ef1f205 100644
--- a/src/CalcManager/pch.h
+++ b/src/CalcManager/pch.h
@@ -5,7 +5,7 @@
 
 #include <algorithm>
 #include <array>
-#include <assert.h>
+#include <cassert>
 #include <intsafe.h>
 #include <list>
 #include <ppltasks.h>