Modify rule S5414: move exception code example

rules/S5414/cfamily/rule.adoc

@@ -1,24 +1,22 @@
 == Why is this an issue?
 
-Mixing (non-const) ``++public++`` and ``++private++`` data members is a bad practice because it causes confusion about the intention of the class:
+Mixing (non-const) ``++public++`` and ``++private++`` data members is a bad practice because it confuses the intention of the class:
 
 * If the class is a collection of loosely related values, all the data members should be ``++public++``.
 * On the other hand, if the class is trying to maintain an invariant, all the data members should be ``++private++``.
 
-If we mix data members with different levels of accessibility, the purpose of the class is muddled.
+If we mix data members with different levels of accessibility, we lose clarity as to the purpose of the class.
 
 
 === Noncompliant code example
 
 [source,cpp]
 ----
-class MyClass // Noncompliant
-{
+class MyClass { // Noncompliant
 public:
   int firstNumber1() const { return firstNumber; }
   void setFirstNumber(int firstNumber) { this->firstNumber = firstNumber; }
   int secondNumber = 2;
-  const int constNumber = 0; // const data members are fine
 private:
   int firstNumber = 1;
 };
@@ -29,12 +27,10 @@ private:
 
 [source,cpp]
 ----
-class MyClass // Depending on the case, the solution might be different. Here, since this class does not enforce any invariant, we make all the data members public
-{
+class MyClass { // Depending on the case, the solution might be different. Here, since this class does not enforce any invariant, we make all the data members public
 public:
   int firstNumber;
   int secondNumber;
-  const int constNumber = 0;
 };
 ----
 
@@ -43,11 +39,27 @@ public:
 
 Since ``++const++`` data members cannot be modified, it's not breaking encapsulation to make a const value public, even in a class that enforces an invariant.
 
+[source,cpp]
+----
+class MyClass { // Compliant by exception
+public:
+  const int constNumber = 0; // const data members are fine
+private:
+  int number = 1;
+};
+----
+
 
 == Resources
 
-* https://github.com/isocpp/CppCoreGuidelines/blob/036324/CppCoreGuidelines.md#c134-ensure-all-non-const-data-members-have-the-same-access-level[{cpp} Core Guidelines C.134]: Ensure all non-const data members have the same access level
-* https://github.com/isocpp/CppCoreGuidelines/blob/036324/CppCoreGuidelines.md#c9-minimize-exposure-of-members[{cpp} Core Guidelines C.9]: Minimize exposure of members
+=== Documentation
+
+* Wikipedia - https://en.wikipedia.org/wiki/Class_invariant[Class invariant]
+
+=== External coding guidelines
+
+* {cpp} Core Guidelines - https://github.com/isocpp/CppCoreGuidelines/blob/036324/CppCoreGuidelines.md#c134-ensure-all-non-const-data-members-have-the-same-access-level[C.134: Ensure all non-const data members have the same access level]
+* {cpp} Core Guidelines - https://github.com/isocpp/CppCoreGuidelines/blob/036324/CppCoreGuidelines.md#c9-minimize-exposure-of-members[C.9: Minimize exposure of members]
 
 
 ifdef::env-github,rspecator-view[]
@@ -79,7 +91,7 @@ Secondaries: one public and one private data member.
 Second, is this rule about having in the same class members that are both non-``++const++`` and ``++public++`` along with members that are ``++private++`` with whatever ``++const++``-ness? Because it is not clear to me from the title and description.
 
 
-In fact, after multiple readings and some cogitation I think this is about having modifiable, ``++public++`` members in a class with ... _anything_ else in it? Because if I can modify the public members directly then what's the point of having methods? They certainly won't be able to notice/act on changes to the public members. 
+In fact, after multiple readings and some cogitation I think this is about having modifiable, ``++public++`` members in a class with ... _anything_ else in it? Because if I can modify the public members directly then what's the point of having methods? They certainly won't be able to notice/act on changes to the public members.
 
 
 And finally, I suggest the 2ndary locations highlight every public non-``++const++`` member, not just one of them.