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

Chapter 4. Global Variables and Functions

In Chapter 3, Introducing Solidity, you learned about Solidity data types in detail. Data types can be value or reference types. Some reference types such as structs and arrays also have data locations—memory and storage associated with them. Variables could be state variables or variables defined locally within functions. This chapter will focus on variables, their scoping rules, declaration and initialization, conversion rules hoisting, and variables available globally to all contracts. Some global functions will also be discussed in this chapter.

We will cover the following topics in this chapter:

  • The var data type
  • Variable scoping
  • Variable conversion
  • Variable hoisting
  • Block related global variables
  • Transaction related global variables
  • Mathematical and cryptographic global functions
  • Addressing related global variables and functions
  • Contract-related global variables and functions