weird error on deleting a variable

Question

So I got a class A and class B where class A is the base class of class B. However when I do something like this:

int main()
{
   B der(222);
   A* test;
   test = &der;
   delete test;
}

I got an error:

debug assertion failed!

program:.......
line 52 

Expression:_BLOCK_TYPE_IS_VALID(pHead0>nBlockUse)

any idea?

`der` has automatic storage. It will be de-allocated automatically. Calling `delete` on its address is illegal (and causes undefined behaviour). — jogojapan, Feb 25 '13 at 04:20
Every delete should be countered with a new. Use both or neither. — Drew Dormann, Feb 25 '13 at 04:21
@smithNeil: Please upvote and accept (one of) the below answers when you've gotten the answer :) — legends2k, Jun 19 '13 at 12:47

score 3 · Answer 1 · answered Feb 25 '13 at 04:21

3

You can't call delete on a variable that you didn't manually allocate memory for.

answered Feb 25 '13 at 04:21

David Kiger

1,958
1
16
25

score 2 · Answer 2 · answered Feb 25 '13 at 04:26

In your code der is not a dynamically allocated object. ie, it is not allocated using new. So you should not use delete on that object. der object would be automatically destroyed once it goes out of scope. If you want to use delete, then you should create the object using new

A * test = new B(222);
delete test;

weird error on deleting a variable

2 Answers2