简单检查dynamic_cast c ++

Question

I do a dynamic_cast and want to check if the cast succeeds.

I am doing a basic null pointer check now. It like this:

A *temp_ptr = dynamic_cast<A *>(obj_ptr);
if( (temp_ptr) && (temp_ptr->some_function()))
{
      // do something if the function returns true
}
else
{
      // cast failed or function returns false
      // continue with normal execution
}

Is this fine or do I need to use assert ? All I care about is that particular function. Is there any other check that I should use ?

Would it pass a code review ?

Answer 1

The check of the results of the dynamic_cast protect the code from doing things incorrectly. An assert protects the program from programmers writing things incorrectly.

Whether you should assert depends on whether it is a mistake for an object to not be of the target type of your dynamic_cast . If coming into this code you expect a mix of objects, some of which are and some of which are not of type A , then an assert would fire for legitimate usage. If every object at this point is expected to be of type A and an object not of that type indicates a programming error, then an assert makes sense, at least in debug builds.