As we know, there is four differences between debug mode and release mode, .ie.,

1. heap layout (you may have heap overwrite in release mode - this will cause 90% of all problems),

2. compilation (check conditional compilation statements, assertion functions etc.),

3. pointer support (no padding in release mode which may increase chances of a pointer to point into sky)

4. optimization.

Here I am trying to understand them as much as I can. The following is the parts I don't really understand.

As for 1, what is heap overwrite?

As for 3, what is padding for pointer?

As for 4, what is the difference in optimization in terms of release and debug mode?