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

Creating contracts


There are the following two ways of creating and using a contract in Solidity:

  • Using the new keyword
  • Using the address of the already deployed contract

Using the new keyword

The new keyword in Solidity deploys and creates a new contract instance. It initializes the contract instance by deploying the contract, initializing the state variables, running its constructor, setting the nonce value to one, and, eventually, returns the address of the instance to the caller. Deploying a contract involves checking whether the requestor has provided enough gas to complete deployment, generating a new account/address for contract deployment using the requestor's address and nonce value, and passing on any Ether sent along with it.

In the next screenshot, two contracts, HelloWorld and client, are defined. In this scenario, one contract (client) deploys and creates a new instance of another contract (HelloWorld). It does so using the new keyword as shown in the following code snippet:

HelloWorld...