A short presentation on "bad" C++ given as a lightening talk at the ACCU 2012 conference. 44 slides in 5 minutes? One of my all time records. Many people have asked for copies of this. For your reference, all idiotic code here is provided under a "do what you like" license. This license allows you to shoot off for own foot as often as you like. No warranty (express or implied) is given that these code snippets WILL destroy your codebase.

1. C++
THE CATHEDRAL
&
THE BIZARRE
PETE GOODLIFFE pete@goodliffe.net @petegoodliffe

2. @petegoodliffe
pete@goodliffe.net
goodliffe.blogspot.com
www.goodliffe.net
P ETE GOOD
PROGRAMME
LIFFE
R / AUTHOR / COLUMNIST / TEACHER ★ CON SCIENTIOUS CODER

7. semicolon overload

8. void foo()
{
};
class Foo
{
public:
Foo() { /* blah */ };
};

9. the non-virtual destructor
class Foo
{
public:
virtual void doSomething() = 0;
};
it’s just common sense, come on people

10. being very certain
if (foo == true) doFoo();

11. being surprised
if (foo && bar || baz) doFoo();

12. very careful delete
if (foo) delete foo;

13. looking like code
void foo(Thing &t)
{
Component *source = t.source;
{
return true;
}
return false;
}

14. in(line) sanity
in .h...
class Foo
{
public:
void MyMethod();
};
in .cpp:
inline void Foo::MyMethod()
{ /* do tonnes of stuff */ }

15. the namespace class

16. not using initialiser lists

17. wrong order initialiser lists

18. any warnings

19. the wrong type of
inheritance

20. writing your own list

21. or pair

22. or string

23. or list

24. or...

25. const (in)correctness
I said...
void useFoo(const Foo &foo);
Chinese whispers…
void useFoo(Foo &foo); // fred: i had to remove
//constness, as we adjust foo
// before using it

26. delete disaster
int *foo = new int [10];
delete foo;

27. doing nothing in style
bool Foo::ThingChanged(Thing *param, int value)
{
switch(param->GetTag())
{
default:
break;
}
return true;
}

29. rule of three

31. stupid long functions

32. ascii art “standard” header
/*------------------------------------------------------------
Function:
Enter:
Exit:
Notes :
----------------------------------------------------------*/
void Foo::DoThing(Thing *pThing)
{
//… stuff

33. just one more parameter
it’s only wafer theeeen...

34. the early return
void Foo::DoSomethingAwesome()
{
evilMachinations();
// fred: the app seems to crash with the code below
return;
otherEvilMachinations();
}

35. inconsistency
naming
spacing
pointers/references

36. the helpful comment
void Foo::ItWasBuggyButIFixedItCozIAmGreat()
{
// [geoff] Added this, it was responsible for
// bugs #234 an #9087
if (foo == 23) ...
}

37. the wrong members
don’t use any member variables
static methods placed here because that’s
“where it’s used”

38. making casual friends
class Foo
{
// because we need to get to…
friend class CompletelyUnrelated;
};

39. leaving helpful notes
or questions in the code
//fred: why set it to 24????

40. protected member variables
for convenience

41. commenting out code
large swathes of it

42. calling everything foo

43. @petegoodliffe
pete@goodliffe.net
goodliffe.blogspot.com
www.goodliffe.net

44. BUMPH DULL, but important ★
THIS DOCUMENT WAS CREATED BY PETE GOODLIFFE
IT IS COPYRIGHT // © 2012 PETE GOODLIFFE
>> ALL RIGHTS RESERVED
>> ALL THOUGHTS ARE OWNED
>> PHOTOS AND IMAGES ARE MOSTLY
SOURCED FROM THE WEB
THANK YOU FOR READING // I HOPE IT WAS USEFUL
Version 1.0 2012-04-25