Tutorial: Refactor MathFunctions code

Help/guide/tutorial/Step2/MathFunctions/MathFunctions.cxx

+#include "MathFunctions.h"
+
+#include "mysqrt.h"
+
+namespace mathfunctions {
+  double sqrt(double x)
+  {
+    return detail::mysqrt(x);
+  }
+}
\ No newline at end of file

Help/guide/tutorial/Step2/MathFunctions/MathFunctions.h

-double mysqrt(double x);
+#pragma once
+
+namespace mathfunctions {
+  double sqrt(double x);
+}

Help/guide/tutorial/Step2/MathFunctions/mysqrt.cxx

+#include "mysqrt.h"
+
 #include <iostream>
 
 // a hack square root calculation using simple operations

Help/guide/tutorial/Step2/MathFunctions/mysqrt.h

+#pragma once
+
+namespace mathfunctions {
+  namespace detail {
+    double mysqrt(double x);
+  }
+}
\ No newline at end of file

Help/guide/tutorial/Step3/MathFunctions/CMakeLists.txt

-add_library(MathFunctions mysqrt.cxx)
+add_library(MathFunctions MathFunctions.cxx mysqrt.cxx)
 
 # TODO 1: State that anybody linking to MathFunctions needs to include the
 # current source directory, while MathFunctions itself doesn't.

Help/guide/tutorial/Step3/MathFunctions/MathFunctions.cxx

+#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
+  }
+}
\ No newline at end of file

Help/guide/tutorial/Step3/MathFunctions/MathFunctions.h

-double mysqrt(double x);
+#pragma once
+
+namespace mathfunctions {
+  double sqrt(double x);
+}

Help/guide/tutorial/Step3/MathFunctions/mysqrt.cxx

-#include <iostream>
+#include "mysqrt.h"
 
-#include "MathFunctions.h"
+#include <iostream>
 
+namespace mathfunctions {
+namespace detail {
 // a hack square root calculation using simple operations
 double mysqrt(double x)
 {
@@ -22,3 +24,5 @@ double mysqrt(double x)
   }
   return result;
 }
+}
+}

Help/guide/tutorial/Step3/MathFunctions/mysqrt.h

+#pragma once
+
+namespace mathfunctions {
+  namespace detail {
+    double mysqrt(double x);
+  }
+}
\ No newline at end of file

Help/guide/tutorial/Step3/tutorial.cxx

@@ -6,9 +6,7 @@
 #include "TutorialConfig.h"
 
 // should we include the MathFunctions header?
-#ifdef USE_MYMATH
-#  include "MathFunctions.h"
-#endif
+#include "MathFunctions.h"
 
 int main(int argc, char* argv[])
 {
@@ -23,12 +21,7 @@ int main(int argc, char* argv[])
   // convert input to double
   const double inputValue = std::stod(argv[1]);
 
-  // which square root function should we use?
-#ifdef USE_MYMATH
-  const double outputValue = mysqrt(inputValue);
-#else
-  const double outputValue = sqrt(inputValue);
-#endif
+  const double outputValue = mathfunctions::sqrt(inputValue);
 
   std::cout << "The square root of " << inputValue << " is " << outputValue
             << std::endl;