On 10 ???, 07:13, OuFeRRaT <oufer...@[EMAIL PROTECTED]
> wrote:
> "RTTI should only be used sparingly in C++ programs. There are several
> reasons for this. Most im****tantly, other language mechanisms such as
> polymorphism and templates are almost always superior to RTTI. As with
> everything, there are exceptions, but the usual rule concerning RTTI
> is more or less the same as with goto statements. Do not use it as a
> shortcut around proper, more robust design. Only use RTTI if you have
> a very good reason to do so and only use it if you know what you're
> doing." as cited inhttp://en.wikibooks.org/wiki/C%2B%2B_Programming/RTTI
>
> I don't understand the sentence:
> "but the usual rule concerning RTTI is more or less the same as with
> goto statements" can anyone explain it?
The usual rule concerning goto is "don't use it unless you _know_ it's
the most clear way to achieve what you're trying to do here". This
phrase you've cited suggests that the same is applicable to RTTI.
> Furthermore, can we talk about the missues of RTTI?
Well, the most typical anti-pattern is using a series of if-else with
typeid in conditionals:
class object {...};
class foo : public object {...};
class bar : public object {...};
....
void do_something(object* obj)
{
if (typeid(*obj) == typeid(foo))
{
foo* foo = static_cast<foo*>(obj);
// do foo-specific processing here
...
}
else if (typeid(*obj) == typeid(bar))
{
bar* bar = static_cast<bar*>(obj);
// do bar-specific processing here
...
}
}
The usual advice in some cases is to use polymorphism - virtual
functions (and, if needed, abstract base cl*****) instead.
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