▫️Lesson 2.1: Introduction to Solidity Programming Language

Module 2: Developing Smart Contracts with Solidity

Objective

To introduce Solidity, the primary programming language used for writing smart contracts on the Ethereum blockchain. This lesson will cover the basics of Solidity, its syntax, and how it is used to create smart contracts that run on the Ethereum Virtual Machine (EVM).

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What is Solidity?

Solidity is a statically-typed programming language designed for developing smart contracts that run on the Ethereum Virtual Machine (EVM). Smart contracts are self-executing contracts with the terms of the agreement directly written into code. Solidity's syntax is similar to that of JavaScript, making it relatively easy to learn for those with programming experience.

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Setting Up the Development Environment

Before diving into Solidity, it's essential to set up a development environment that allows you to write, compile, and deploy smart contracts.

Recommended Tools:

• Remix IDE: An open-source web application that provides an environment for writing Solidity contracts, directly in your browser.

• Truffle Suite: A development environment, testing framework, and asset pipeline for blockchains using the Ethereum Virtual Machine (EVM).

• Ganache: A personal blockchain for Ethereum development you can use to deploy contracts, develop applications, and run tests.

• MetaMask: A crypto wallet and gateway to blockchain apps, useful for interacting with Ethereum networks.

Installation Guides:

• Visit the official websites of these tools for installation instructions. For Remix IDE, no installation is required as it runs in your browser.

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Basic Syntax and Structure of a Solidity Contract

A Solidity smart contract is a collection of code (its functions) and data (its state) that resides at a specific address on the Ethereum blockchain.

Example: A Simple Storage Contract

// Specifies the version of Solidity, using semantic versioning.
pragma solidity ^0.8.0;

// Declares a contract named `SimpleStorage`.
contract SimpleStorage {
    // Declares a state variable `number` of type `uint` (unsigned integer).
    uint number;

    // A function to store a number.
    function store(uint _number) public {
        number = _number;
    }

    // A function to retrieve the stored number.
    function retrieve() public view returns (uint) {
        return number;
    }
}

Key Components:

• Pragma Directive: Specifies the compiler version to be used.

• Contract Declaration: Begins with the contract keyword followed by the contract name.

• State Variables: Variables that permanently store data on the blockchain.

• Functions: Code that can modify state variables and interact with other contracts.

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First Smart Contract

Activity: Write and deploy your first smart contract using Remix IDE.

1. Open Remix IDE in your browser.

2. Create a new Solidity file (.sol) and paste the example contract code.

3. Compile the contract using the Solidity compiler provided in Remix.

4. Deploy the contract to a test network or JavaScript VM provided by Remix.

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Exercise

Hands-On Practice:

• Modify the SimpleStorage contract to include a function that increments the stored number by a value passed as a parameter.

• Deploy your modified contract using Remix IDE and test the new functionality.

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This lesson has provided an introduction to Solidity and the basics of writing and deploying a smart contract. As you become more familiar with Solidity's syntax and features, you'll be better equipped to explore more complex contract structures and functionalities.