Blockchain By Example

Functions

After defining the auction states, it's time to define the functions that handle the auction's functionalities. In Solidity, a function has the same meaning as in any other language, and is declared using the keyword function, as follows:

function function_name(<parameter types>) {internal|external|private|public} [pure|constant|view|payable] [returns (<return types>)]

Like variables, functions can be specified as being external, internal, private, or public, while the default visibility is public. As our first contract, auction, is an abstract contract, we only declare the functions without implementation. They will be implemented later, in a child contract.

Along with the visibility specifier, we can define additional specifiers, ...