Solidity Fundamentals

Level: Beginner Module Title: Build Your First Smart Contract with Solidity

🧠 What You’ll Learn:

• The role of Solidity in Ethereum development

• Solidity syntax and data types

• Writing and understanding a basic smart contract

• Deploying a contract using Remix IDE

📘 Lesson 1: What is Solidity?

Solidity is the main programming language for writing smart contracts on Ethereum. It’s statically typed, supports inheritance, libraries, and complex custom types. Inspired by JavaScript and C++, Solidity allows you to encode logic that executes directly on the blockchain.

Use cases:

• Token creation (ERC-20, ERC-721)

• Decentralized applications (dApps)

• Voting systems

• Escrow and automated payments

📘 Lesson 2: Writing Your First Contract

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract HelloWorld {
    string public message = "Hello, Ethereum!";
}

Explanation:

• pragma: Compiler version

• contract: Smart contract declaration

• string public: A readable string stored on-chain

📘 Lesson 3: Understanding Variables & Functions

uint public count;

function increment() public {
    count += 1;
}

• uint: Unsigned integer

• public: Accessible externally

• function: Defines callable logic

📘 Lesson 4: Deploying with Remix IDE

1. Visit Remix

2. Create a new .sol file

3. Paste your Solidity code

4. Compile with the Solidity Compiler plugin

5. Deploy using JavaScript VM or Injected Web3 (MetaMask)

6. Interact with your contract using Remix's UI