Question

A function with no action
a) is an invalid function
b) produces syntax error
c) is allowed and is known as dummy
function
d) returns zero

Answer 1

the function will return zero

Answer 2

A function which have no action to perform is known as Abstract function in java, or dummy function. The use of such functions are for creating the actions of that function in some different class. These are usually done when the function's work are unknown but the need of the function is known from beforehand.

The class itself is also known as abstract class, where there is at least one abstract function present in it.