Tutorial: Improve Step 1

* Update minimum required version to 3.10
* Use VERSION argument to project command rather than separate variables
* Replace `endif(USE_MYMATH)` with  more modern `endif()`
* Simplify the call to 'configure_file()'
* Add comments to tutorial.cxx to use as anchors in documentation
* Remove CMakeLists and TutorialConfig.h.in files that users should
  create. Consequently, remove Step1 from CMake tests.

Help/guide/tutorial/Step11/CMakeLists.txt

@@ -1,5 +1,7 @@
 cmake_minimum_required(VERSION 3.15)
-project(Tutorial)
+
+# set the project name and version
+project(Tutorial VERSION 1.0)
 
 add_library(tutorial_compiler_flags INTERFACE)
 target_compile_features(tutorial_compiler_flags INTERFACE cxx_std_11)
@@ -13,10 +15,6 @@ target_compile_options(tutorial_compiler_flags INTERFACE
   "$<${msvc_cxx}:$<BUILD_INTERFACE:-W3>>"
 )
 
-# set the version number
-set(Tutorial_VERSION_MAJOR 1)
-set(Tutorial_VERSION_MINOR 0)
-
 # control where the static and shared libraries are built so that on windows
 # we don't need to tinker with the path to run the executable
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}")
@@ -26,10 +24,7 @@ set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${PROJECT_BINARY_DIR}")
 option(BUILD_SHARED_LIBS "Build using shared libraries" ON)
 
 # configure a header file to pass the version number only
-configure_file(
-  "${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
-  "${PROJECT_BINARY_DIR}/TutorialConfig.h"
-  )
+configure_file(TutorialConfig.h.in TutorialConfig.h)
 
 # add the MathFunctions library
 add_subdirectory(MathFunctions)

Help/guide/tutorial/Step11/tutorial.cxx

@@ -16,7 +16,8 @@ int main(int argc, char* argv[])
     return 1;
   }
 
-  double inputValue = std::stod(argv[1]);
+  // convert input to double
+  const double inputValue = std::stod(argv[1]);
 
   const double outputValue = mathfunctions::sqrt(inputValue);