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.

Help/guide/tutorial/Step2/CMakeLists.txt

@@ -7,36 +7,20 @@ project(Tutorial VERSION 1.0)
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 
-# TODO 7: Create a variable USE_MYMATH using option and set default to ON
-
 # configure a header file to pass some of the CMake settings
 # to the source code
 configure_file(TutorialConfig.h.in TutorialConfig.h)
 
-# TODO 8: Use list() and APPEND to create a list of optional libraries
-# called  EXTRA_LIBS and a list of optional include directories called
-# EXTRA_INCLUDES. Add the MathFunctions library and source directory to
-# the appropriate lists.
-#
-# Only call add_subdirectory and only add MathFunctions specific values
-# to EXTRA_LIBS and EXTRA_INCLUDES if USE_MYMATH is true.
-
 # TODO 2: Use add_subdirectory() to add MathFunctions to this project
 
 # add the executable
 add_executable(Tutorial tutorial.cxx)
 
-# TODO 9: Use EXTRA_LIBS instead of the MathFunctions specific values
-# in target_link_libraries.
-
 # TODO 3: Use target_link_libraries to link the library to our executable
 
 # TODO 4: Add MathFunctions to Tutorial's target_include_directories()
 # Hint: ${PROJECT_SOURCE_DIR} is a path to the project source. AKA This folder!
 
-# TODO 10: Use EXTRA_INCLUDES instead of the MathFunctions specific values
-# in target_include_directories.
-
 # add the binary tree to the search path for include files
 # so that we will find TutorialConfig.h
 target_include_directories(Tutorial PUBLIC

Help/guide/tutorial/Step2/MathFunctions/CMakeLists.txt

@@ -1,2 +1,7 @@
 # TODO 1: Add a library called MathFunctions
 # Hint: You will need the add_library command
+
+# TODO 7: Create a variable USE_MYMATH using option and set default to ON
+
+# TODO 8: If USE_MYMATH is ON, use target_compile_definitions to pass
+# USE_MYMATH as a precompiled definition to our source files

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

@@ -0,0 +1,15 @@
+#include "MathFunctions.h"
+
+// TODO 11: include cmath
+
+// TODO 10: Wrap the mysqrt include in a precompiled ifdef based on USE_MYMATH
+#include "mysqrt.h"
+
+namespace mathfunctions {
+double sqrt(double x)
+{
+  // TODO 9: If USE_MYMATH is defined, use detail::mysqrt.
+  // Otherwise, use std::sqrt.
+  return detail::mysqrt(x);
+}
+}

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

@@ -1 +1,5 @@
-double mysqrt(double x);
+#pragma once
+
+namespace mathfunctions {
+double sqrt(double x);
+}

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

@@ -1,5 +1,9 @@
+#include "mysqrt.h"
+
 #include <iostream>
 
+namespace mathfunctions {
+namespace detail {
 // a hack square root calculation using simple operations
 double mysqrt(double x)
 {
@@ -20,3 +24,5 @@ double mysqrt(double x)
   }
   return result;
 }
+}
+}

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

@@ -0,0 +1,7 @@
+#pragma once
+
+namespace mathfunctions {
+namespace detail {
+double mysqrt(double x);
+}
+}

Help/guide/tutorial/Step2/TutorialConfig.h.in

@@ -1,5 +1,3 @@
 // the configured options and settings for Tutorial
 #define Tutorial_VERSION_MAJOR @Tutorial_VERSION_MAJOR@
 #define Tutorial_VERSION_MINOR @Tutorial_VERSION_MINOR@
-
-// TODO 13: use cmakedefine to define USE_MYMATH

Help/guide/tutorial/Step2/tutorial.cxx

@@ -3,11 +3,8 @@
 #include <iostream>
 #include <string>
 
-#include "TutorialConfig.h"
-
-// TODO 11: Only include MathFunctions if USE_MYMATH is defined
-
 // TODO 5: Include MathFunctions.h
+#include "TutorialConfig.h"
 
 int main(int argc, char* argv[])
 {
@@ -22,9 +19,7 @@ int main(int argc, char* argv[])
   // convert input to double
   const double inputValue = std::stod(argv[1]);
 
-  // TODO 12: Use mysqrt if USE_MYMATH is defined and sqrt otherwise
-
-  // TODO 6: Replace sqrt with mysqrt
+  // TODO 6: Replace sqrt with mathfunctions::sqrt
 
   // calculate square root
   const double outputValue = sqrt(inputValue);