What is the difference between unary operator and function?

Question

As i have learnt that the sizeof() is an unary operator not a function why it is said so? Also what are the characteristics of it because of why we need to describe the difference and what about the gets() and getchar()?

Answer 1

Additional resource

https://learntechway.com/sizeof-operator-or-functionwhy-cant-it-be-overloaded/

https://stackoverflow.com/questions/3954844/sizeof-operator-or-function