3 files changed, 36 insertions, 0 deletions
diff --git a/Help/guide/tutorial/Step5/MathFunctions/CMakeLists.txt b/Help/guide/tutorial/Step5/MathFunctions/CMakeLists.txt
new file mode 100644
index 0000000..b12f27d
--- /dev/null
+++ b/Help/guide/tutorial/Step5/MathFunctions/CMakeLists.txt
@@ -0,0 +1,11 @@
+add_library(MathFunctions mysqrt.cxx)
+
+# state that anybody linking to us needs to include the current source dir
+# to find MathFunctions.h, while we don't.
+target_include_directories(MathFunctions
+          INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}
+          )
+
+# install rules
+install(TARGETS MathFunctions DESTINATION lib)
+install(FILES MathFunctions.h DESTINATION include)
diff --git a/Help/guide/tutorial/Step5/MathFunctions/MathFunctions.h b/Help/guide/tutorial/Step5/MathFunctions/MathFunctions.h
new file mode 100644
index 0000000..cd36bcc
--- /dev/null
+++ b/Help/guide/tutorial/Step5/MathFunctions/MathFunctions.h
@@ -0,0 +1 @@
+double mysqrt(double x);
diff --git a/Help/guide/tutorial/Step5/MathFunctions/mysqrt.cxx b/Help/guide/tutorial/Step5/MathFunctions/mysqrt.cxx
new file mode 100644
index 0000000..abe767d
--- /dev/null
+++ b/Help/guide/tutorial/Step5/MathFunctions/mysqrt.cxx
@@ -0,0 +1,24 @@
+#include <iostream>
+
+#include "MathFunctions.h"
+
+// a hack square root calculation using simple operations
+double mysqrt(double x)
+{
+  if (x <= 0) {
+    return 0;
+  }
+
+  double result = x;
+
+  // do ten iterations
+  for (int i = 0; i < 10; ++i) {
+    if (result <= 0) {
+      result = 0.1;
+    }
+    double delta = x - (result * result);
+    result = result + 0.5 * delta / result;
+    std::cout << "Computing sqrt of " << x << " to be " << result << std::endl;
+  }
+  return result;
+}