Introduction

This tutorial aims to introduce you to the Ethereum blockchain, its architecture, and its key components. You will learn about Ethereum's purpose, how it works, and how to write smart contracts using Solidity, Ethereum's primary programming language.

Prerequisites:

To get the most out of this tutorial, you should have a basic understanding of blockchain technology and some experience with programming, preferably with JavaScript or a similar language.

Step-by-Step Guide

2.1 Ethereum Blockchain

Ethereum is an open-source, blockchain-based platform that enables developers to build and deploy decentralized applications (dApps). It uses its cryptocurrency, Ether (ETH), for transaction fees and computational services on the network.

2.2 Ethereum Architecture

The Ethereum blockchain consists of interconnected blocks, each containing a list of transactions. When a new block is created, it is added to the blockchain. Ethereum's architecture consists of three layers:

• Application Layer: This is where the dApps are stored and executed.
• Ethereum Virtual Machine (EVM): This is a runtime environment that executes all smart contracts on Ethereum.
• Network Layer: This layer ensures the propagation of transactions and blocks to all nodes on the network.

2.3 Smart Contracts

Smart contracts are self-executing contracts with the terms of the agreement directly written into code. They run on the Ethereum blockchain and are tamper-proof. Once deployed, they cannot be modified.

Code Examples

3.1 Simple Smart Contract

Below is a simple smart contract written in Solidity:

pragma solidity ^0.8.0;

contract SimpleContract {
    uint public data;

    function set(uint x) public {
        data = x;
    }

    function get() public view returns (uint) {
        return data;
    }
}

• pragma solidity ^0.8.0; specifies the version of Solidity the contract uses.
• contract SimpleContract {...} is the contract definition. A contract is a collection of code and data that resides at a specific address on the Ethereum blockchain.
• uint public data; this declares a state variable called data of type uint.
• function set(uint x) public {...} and function get() public view returns (uint) {...} are functions that allow us to modify and retrieve the value of the variable data.

To deploy and use this contract, you would typically use a framework like Truffle or Hardhat, or a library like Web3.js or Ethers.js.

Summary

In this tutorial, you've learned about the Ethereum blockchain, its architecture, and its key components. You've been introduced to the concept of smart contracts and have seen a basic example of one.

To continue learning about Ethereum and smart contract development, consider exploring more complex contract examples, learn about Ethereum's Gas, or dive into topics like contract testing and security.

Practice Exercises

1. Write a smart contract for a simple voting system.
2. Modify the above contract to prevent the same person from voting twice.
3. Write a smart contract that implements a basic token system.

These exercises will help you understand how to write more complex contracts and interact with them. Experimenting with different scenarios will deepen your understanding of how Ethereum and smart contracts work.