Fix error in text in the solution of exercice 33.

3-Operators/1c-SolutionExercice33.ipynb

@@ -32,7 +32,7 @@
     "You should of course heed the warning and fix your code:\n",
     "\n",
     "* Make `operator double` explicit. Except in very specific cases, I advise you to always make such conversion operators explicit to avoid unintended side effects as the one we've just got.\n",
-    "* If commutativity is important for you, make `operator*` a friend function instead of a method and provide both ordering of arguments. \n",
+    "* If commutativity is important for you, make `operator*` a free function instead of a method and provide both ordering of arguments. \n",
     "\n",
     "The solution file implements both these modifications."
    ]
 %% Cell type:markdown id: tags:
 
 # [Getting started in C++](/) - [Operators](/notebooks/3-Operators/0-main.ipynb) - [TP 8 - Solution](/notebooks/3-Operators/1b-TP.ipynb)
 
 %% Cell type:markdown id: tags:
 
 <h1>Table of contents<span class="tocSkip"></span></h1>
 <div class="toc"><ul class="toc-item"><li><span><a href="#EXERCICE-33:-commutativity" data-toc-modified-id="EXERCICE-33:-commutativity-1">EXERCICE 33: commutativity</a></span></li></ul></div>
 
 %% Cell type:markdown id: tags:
 
 ### EXERCICE 33: commutativity
 
 What happens in fact is that `operator*` is not commutative: it expects as first argument an object and as second argument an integer.
 
 So why does it work nonetheless?
 
 `operator*(int, PowerOfTwoApprox)` is not defined... but addition between an integer and a double is obviously possible, AND you've just defined before an implicit conversion to `double`.
 
 You should of course heed the warning and fix your code:
 
 * Make `operator double` explicit. Except in very specific cases, I advise you to always make such conversion operators explicit to avoid unintended side effects as the one we've just got.
-* If commutativity is important for you, make `operator*` a friend function instead of a method and provide both ordering of arguments.
+* If commutativity is important for you, make `operator*` a free function instead of a method and provide both ordering of arguments.
 
 The solution file implements both these modifications.
 
 %% Cell type:markdown id: tags:
 
 © _CNRS 2016_ - _Inria 2018-2019_
 _This notebook is an adaptation of a lecture prepared and redacted by David Chamont (CNRS) under the terms of the licence [Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)](http://creativecommons.org/licenses/by-nc-sa/4.0/)_
 _The present version has been redacted by Sébastien Gilles and Vincent Rouvreau (Inria)_