Abstract contracts

Abstract contracts are contracts that have partial function definitions. You cannot create an instance of an abstract contract. An abstract contract must be inherited by a child contract to utilize its functions.

Abstract contracts help in defining the structure of a contract, and any class inheriting from it must ensure to provide an implementation for them. If the child contract does not provide the implementation for incomplete functions, its instance cannot be created. The function signature is terminated using a semicolon (;). Solidity provides an abstract keyword to mark a contract as abstract. This is a relatively new keyword addition and it was not part of prior versions. A contract becomes an abstract contract when it consists of functions without any implementation.

The following code snippet is an implementation of an abstract contract.

The abstractHelloWorld contract is an abstract contract as it contains a couple of functions without any...