Book Image

Solidity Programming Essentials - Second Edition

By : Ritesh Modi
Book Image

Solidity Programming Essentials - Second Edition

By: Ritesh Modi

Overview of this book

Solidity is a high-level language for writing smart contracts, and the syntax has large similarities with JavaScript, thereby making it easier for developers to learn, design, compile, and deploy smart contracts on large blockchain ecosystems including Ethereum and Polygon among others. This book guides you in understanding Solidity programming from scratch. The book starts with step-by-step instructions for the installation of multiple tools and private blockchain, along with foundational concepts such as variables, data types, and programming constructs. You’ll then explore contracts based on an object-oriented paradigm, including the usage of constructors, interfaces, libraries, and abstract contracts. The following chapters help you get to grips with testing and debugging smart contracts. As you advance, you’ll learn about advanced concepts like assembly programming, advanced interfaces, usage of recovery, and error handling using try-catch blocks. You’ll also explore multiple design patterns for smart contracts alongside developing secure smart contracts, as well as gain a solid understanding of writing upgradable smart concepts and data modeling. Finally, you’ll discover how to create your own ERC20 and NFT tokens from scratch. By the end of this book, you will be able to write, deploy, and test smart contracts in Ethereum.
Table of Contents (21 chapters)
1
Part 1: The Fundamentals of Solidity and Ethereum
7
Part 2: Writing Robust Smart Contracts
13
Part 3: Advanced Smart Contracts

Understanding Boolean

Solidity, as with any programming language, provides a Boolean data type. The bool data type can be used to represent scenarios that have binary results, such as true or false, and 1 or 0. The valid values for this data type are true and false. Note that bool data types in Solidity cannot be converted to integers as they can in other programming languages. It's a value type, and any assignment to other Boolean variables creates a new copy. The default value for bool in Solidity is false.

A bool data type is declared and assigned a value, as shown in the following code:

bool isPaid = true;

It can be modified within contracts and can be used in both incoming and outgoing parameters and the return value, as shown in the following code listing:

// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.7.0 <0.9.0;
contract BoolContract {
    bool isPaid = true;
    
    function manageBool...