Book Image

Solidity Programming Essentials

Book Image

Solidity Programming Essentials

Overview of this book

Solidity is a contract-oriented language whose syntax is highly influenced by JavaScript, and is designed to compile code for the Ethereum Virtual Machine. Solidity Programming Essentials will be your guide to understanding Solidity programming to build smart contracts for Ethereum and blockchain from ground-up. We begin with a brief run-through of blockchain, Ethereum, and their most important concepts or components. You will learn how to install all the necessary tools to write, test, and debug Solidity contracts on Ethereum. Then, you will explore the layout of a Solidity source file and work with the different data types. The next set of recipes will help you work with operators, control structures, and data structures while building your smart contracts. We take you through function calls, return types, function modifers, and recipes in object-oriented programming with Solidity. Learn all you can on event logging and exception handling, as well as testing and debugging smart contracts. By the end of this book, you will be able to write, deploy, and test smart contracts in Ethereum. This book will bring forth the essence of writing contracts using Solidity and also help you develop Solidity skills in no time.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Abstract contracts


Abstracts 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 for utilizing 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, even its instance cannot be created. The function signatures terminate using the semicolon, ;, character. There is no Solidity-provided keyword to mark a contract as abstract. A contract becomes an abstract class if it has functions without implementation.

The screenshot shown next is an implementation of an abstract contract. The abstractHelloWorld contract is an abstract contract as it contains a couple of functions without any definitions. GetValue and SetValue are function signatures without any implementation. There is another...