What is the cost of sizeof?

Question

What is the cost of sizeof?

I would expect:

• sizeof(someclass) can be known at compile time
• sizeof(someStaticArray) can be known at compile time

Answer 1

sizeof only works at compile time. A dynamic array will use a pointer to dynamically allocated memory which will not be included in the result. You'll only get the size of the pointer and housekeeping information (array length, etc).