Interview : function pointers vs switch case

Question

During my Interview, I was asked to implement a state machine for a system having 100 states where each state in turn has 100 events, I answered 3 following approaches:

• if-else
• switch-case
• function pointers

If-else is obviously not suited for such a state machine, hence main comparison was between switch-case vs function pointers, here is the comparison as per my understanding:

• Speed wise both are almost same.
• Switch-case is less modular than function-pointers
• Function-pointers has more memory overhead.

Could someone confirm if above understanding is correct ?

Answer 1

There might be a variant of the function pointer approach: a struct which includes a function pointer as well as other information. So you could let one function handle several cases.

Beside of this, I think you are right. Plus, I would consider the overhead concerning memory and speed worth to be considered, but hopefully small enough to be ignored at the end.