Types notebook: add the possibility to declare std::string from string...

Types notebook: add the possibility to declare std::string from string litterals with 's' suffix (I learned that while preparing string view notebooks).

1-ProceduralProgramming/3-Types.ipynb

@@ -690,7 +690,36 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "Please notice C++17 introduced [std::string_view](https://en.cppreference.com/w/cpp/header/string_view) which is more efficient than `std::string` for some operations (it is presented [in appendix](../7-Appendix/StringView.ipynb) but if it's your first reading it's a bit early to tackle it now).\n"
+    "FYI, C++ 14 introduced a suffix to facilitate declaration of a `std::string` from a string litterals... but which requires to add a specific `using namespace` first (we will see that those are in a [much later notebook](../6-InRealEnvironment/5-Namespace.ipynb)). "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "#include <string>\n",
+    "\n",
+    "using namespace std::string_literals;\n",
+    "\n",
+    "auto hello_str = \"Hello world\"; // declares a char*\n",
+    "auto hello = \"Hello world\"s;  // declares a std::string - requires first the using namespace directive\n",
+    "std::string hello_string(\"Hello world\"); // the 'classic' way to define a std::string"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Not sure it it is entirely worth it (maybe when you define loads of `std::string` is a same file?) but you may see that in an existing program."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "FYI as well, C++17 introduced [std::string_view](https://en.cppreference.com/w/cpp/header/string_view) which is more efficient than `std::string` for some operations (it is presented [in appendix](../7-Appendix/StringView.ipynb) but if it's your first reading it's a bit early to tackle it now)."
    ]
   },
   {