Book Image

Blockchain Developer's Guide

By : Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty
Book Image

Blockchain Developer's Guide

By: Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty

Overview of this book

Blockchain applications provide a single-shared ledger to eliminate trust issues involving multiple stakeholders. It is the main technical innovation of Bitcoin, where it serves as the public ledger for Bitcoin transactions. Blockchain Developer's Guide takes you through the electrifying world of blockchain technology. It begins with the basic design of a blockchain and elaborates concepts, such as Initial Coin Offerings (ICOs), tokens, smart contracts, and other related terminologies. You will then explore the components of Ethereum, such as Ether tokens, transactions, and smart contracts that you need to build simple DApps. Blockchain Developer's Guide also explains why you must specifically use Solidity for Ethereum-based projects and lets you explore different blockchains with easy-to-follow examples. You will learn a wide range of concepts - beginning with cryptography in cryptocurrencies and including ether security, mining, and smart contracts. You will learn how to use web sockets and various API services for Ethereum. By the end of this Learning Path, you will be able to build efficient decentralized applications. This Learning Path includes content from the following Packt products: • Blockchain Quick Reference by Brenn Hill, Samanyu Chopra, Paul Valencourt • Building Blockchain Projects by Narayan Prusty
Table of Contents (37 chapters)
Title Page
About Packt

Programming in Solidity

In this section, we will be discussing the structure and elements of a Solidity source file; we will discuss the layout, structure, data types, its types, units, controls, expressions, and other aspects of Solidity. The format extension of a solidity file is .sol.

Laying out a Solidity file

Solidity is going through active development and has lot of regular changes and suggestions from a huge community; hence, it is important to specify the version of a solidity file at the start of the source file, to avoid any conflict. This is achieved by the Pragma version. This is defined at the start of the solidity file so that any person looking to run the file knows about the previous version. Take a look at this code:

pragma solidity ^0.4.24;

By specifying a version number, that specific source file will compile with a version earlier or later than the specified version number.


Importing files

Similar to ECMAScript, a Solidity file is declared using the import statement as follows...