diff --git a/6-InRealEnvironment/2-FileStructure.ipynb b/6-InRealEnvironment/2-FileStructure.ipynb
index 0e24458c4276ab7dcc610399afa689fcc059284e..45dc4d5294a835e20a76007c5b4a03e095c2b257 100644
--- a/6-InRealEnvironment/2-FileStructure.ipynb
+++ b/6-InRealEnvironment/2-FileStructure.ipynb
@@ -593,7 +593,7 @@
     "#ifndef HELLO_HPP\n",
     "#define HELLO_HPP\n",
     "\n",
-    "void hello();\n",
+    "void Hello();\n",
     "\n",
     "#endif // HELLO_HPP"
    ]
@@ -664,7 +664,7 @@
     "\n",
     "int main(int argc, char** argv)\n",
     "{\n",
-    "    hello();\n",
+    "    Hello();\n",
     "    \n",
     "    return EXIT_SUCCESS;\n",
     "}"
diff --git a/6-InRealEnvironment/4-ThirdParty.ipynb b/6-InRealEnvironment/4-ThirdParty.ipynb
index 7075dee59214fa61c8ea813e442a37987e357011..329e41427e8edb7bf9dc5f3518fc7e596227d0c8 100644
--- a/6-InRealEnvironment/4-ThirdParty.ipynb
+++ b/6-InRealEnvironment/4-ThirdParty.ipynb
@@ -31,7 +31,7 @@
     "\n",
     "* Fixing the warnings from the third-party library yourself is a dead-end: you would have to redo-it at each upgrade of the library... and doing it in the first place may not be that easy with a base code you do not know. \n",
     "* Of course, you may ask the library developers to fix it, or even better provide a **pull request** to do it for them... but they may not be keen to accept it, and argue they know what they're doing and that you should shut the damn compiler warning up. But you really shouldn't: the warnings you want to use or not should be dictated by your own needs, not by the third-party libraries.\n",
-    "* Keeping the warning is also bad: as already mentioned if you're letting even 10 warnings in your code you may not see the dangerous 11th a change in the code may produce.\n",
+    "* Keeping the warnings is also bad: as already mentioned if you're letting even 10 warnings in your code you may not see the dangerous 11th a change in the code may produce.\n",
     "\n",
     "## Demo\n",
     "\n",
diff --git a/6-InRealEnvironment/5-Namespace.ipynb b/6-InRealEnvironment/5-Namespace.ipynb
index ed3c4149416cc2d210226405d68c0a3005ca3c5d..312ea0db2125e65eaa6d5aae20a3799f082f0a55 100644
--- a/6-InRealEnvironment/5-Namespace.ipynb
+++ b/6-InRealEnvironment/5-Namespace.ipynb
@@ -188,6 +188,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "// hpp file\n",
+    "\n",
     "namespace MyProject\n",
     "{\n",
     "    namespace Internal\n",
@@ -204,6 +206,8 @@
    "metadata": {},
    "outputs": [],
    "source": [
+    "// cpp file\n",
+    "\n",
     "namespace MyProject\n",
     "{\n",
     "    namespace Internal\n",