Tutorial: Refactor MathFunctions code

Propagate the refactor in Step 10 MathFunctions through all of the
steps. Use MathFunctions/MathFunctions.cxx instead of Tutorial.cxx
to determine which sqrt library is called. Adds .h files which
correspond to their .cxx files by name.

1 files changed, 19 insertions, 0 deletions

diff --git a/Help/guide/tutorial/Step9/MathFunctions/MathFunctions.cxx b/Help/guide/tutorial/Step9/MathFunctions/MathFunctions.cxx
new file mode 100644
index 0000000000..dc28b4b530
--- /dev/null
+++ b/Help/guide/tutorial/Step9/MathFunctions/MathFunctions.cxx
@@ -0,0 +1,19 @@
+#include "MathFunctions.h"
+
+#include <cmath>
+
+#ifdef USE_MYMATH
+#  include "mysqrt.h"
+#endif
+
+namespace mathfunctions {
+double sqrt(double x)
+{
+// which square root function should we use?
+#ifdef USE_MYMATH
+  return detail::mysqrt(x);
+#else
+  return std::sqrt(x);
+#endif
+}
+}