array and polymorphism

[hpsoar]

I have ream Item 3 in the famous More Effective C++, the title
is :Never treat arrays polymorphically. it warn us about misusage of
polymorphism. But I'm just not clear about the rational or reason, can
anyone give me a clearer explanation? and thank you

 

[Alan Woodland]

I have ream Item 3 in the famous More Effective C++, the title
is :Never treat arrays polymorphically. it warn us about misusage of
polymorphism. But I'm just not clear about the rational or reason, can
anyone give me a clearer explanation? and thank you

The example at:

https://www.securecoding.cert.org/c...RR39-CPP.+Do+not+treat+arrays+polymorphically

Seems to demonstrate the problem, and suggest some suitable solutions.

Alan

 

[pasa]

Which part of the item text is unclear or you don't understand?

 

[Ian Collins]

I have ream Item 3 in the famous More Effective C++, the title
is :Never treat arrays polymorphically. it warn us about misusage of
polymorphism. But I'm just not clear about the rational or reason, can
anyone give me a clearer explanation? and thank you

Try compiling the example code and see what happens. The gist of the
problem is arrays of T decaying to pointer to T in function calls. So a
function with a parameter type const Base[] can be passed an array of
Derived[].

 

[Ian Collins]

(e-mail address removed) wrote:

Context, please!

Which part of the item text is unclear or you don't understand?

 

[hpsoar]

(e-mail address removed) wrote:

Context, please!

I think I understand it know, but I think frequently when we want to
manipulate an object we do it with a pointer of its base class type,
and analogically, when we want to manipulate an array of objects we
can naturally use an array of pointers of its base class type. So that
problem proved to be insignificant. What do you think ?

 

[hpsoar]

I think I understand it know, but I think frequently when we want to
manipulate an object we do it with a pointer of its base class type,
and analogically, when we want to manipulate an array of objects we
can naturally use an array of pointers of its base class type. So that
problem proved to be insignificant. What do you think ?

Ok, I wrote those words abouve before I read the article on
https://www.securecoding.cert.org/confluence/display/cplusplus/ARR39-...
, after I accomplish reading, I found myself conformed with the
author, thank you anyway.