Solidity Smart Contract Learning Repository

Highlights

Introduction to Solidity

Learn the fundamentals of Solidity, including how to set up your development environment and write your first smart contract.

pragma solidity ^0.8.0;

contract HelloWorld {
    string public greet = "Hello, World!";
}

Data Types and Variables

Understand different data types and how to declare variables in Solidity.

contract DataTypes {
    uint public myUint = 1;
    string public myString = "Hello";
    address public myAddress = msg.sender;
}

Functions and Modifiers

Explore how to define functions, use function modifiers, and understand their significance.

contract Functions {
    uint public myNumber;

    function setNumber(uint _number) public {
        myNumber = _number;
    }

    function getNumber() public view returns (uint) {
        return myNumber;
    }
}

Inheritance and Interfaces

Dive into contract inheritance and interface implementation to create more modular and reusable code.

contract Parent {
    function sayHello() public pure returns (string memory) {
        return "Hello from Parent";
    }
}

contract Child is Parent {
    function greet() public pure returns (string memory) {
        return sayHello();
    }
}

Project Structure

This repo is organized by topic folders:

• 1-Intro
• 2-State Variables
• 3-Local Variables
• 4-Function
• 5-Constructor
• 6-Data Types
• 7-Array
• 8-Loops
• 9-Conditionals
• 10-Struct
• 11-Mapping
• 12-Storage Locations
• 13-Global Variables
• 14- Contract Balance
• 15-Visibility
• 16-Exercises

Learning Path

Follow folders in order from 1-Intro to 16-Exercises. Each folder contains simple examples for the topic, with 16-Exercises providing TODO-based practice.

How to Run Each Folder (1-16)

There is no single "run" command for the entire repo. Each .sol file is a separate contract that you compile and deploy.

Using Remix (Recommended)

1. Open Remix: https://remix.ethereum.org
2. Create a workspace and import the folder you want (e.g., 7-Array).
3. Open a .sol file in that folder.
4. Set the compiler version to match the file pragma.
5. Compile and deploy.
6. Interact with the contract functions in the Remix UI.

Repeat the same steps for each folder and file you want to try.

Using Hardhat (Local)

1. Copy one folder at a time into contracts/ (for example 7-Array/).
2. Compile with npx hardhat compile.
3. Create a script to deploy and interact with a specific contract.

Example script outline:

// scripts/run.js
const { ethers } = require("hardhat");

async function main() {
  const Contract = await ethers.getContractFactory("ContractNameHere");
  const contract = await Contract.deploy();
  await contract.waitForDeployment();
  console.log("Deployed:", await contract.getAddress());
}

main().catch((error) => {
  console.error(error);
  process.exitCode = 1;
});

Run it with:

npx hardhat run scripts/run.js

Repeat by swapping the folder and contract name you want to test.

Setup and Run in Remix

Remix is a browser-based IDE, so there is nothing to install to compile or run these contracts.

What you need

• A modern web browser (Chrome, Firefox, or Edge).
• Optional: MetaMask if you want to deploy to a testnet. For local testing, Remix VM is enough.

Steps

1. Open Remix: https://remix.ethereum.org
2. Create a workspace:
   • Use File explorers > Workspaces > Create and name it (e.g., solidity-basics).
3. Add the contracts:
   • Drag and drop the folder(s) from this repo into the Remix file explorer, or
   • Copy the .sol files into matching folders in Remix.
4. Compile:
   • Open the Solidity Compiler tab.
   • Set the compiler version that matches the pragma in the file.
   • Click Compile.
5. Deploy and run:
   • Open the Deploy & Run Transactions tab.
   • Choose Remix VM as the environment for local testing.
   • Click Deploy, then interact with the functions below.

Dependencies

• None required for Remix-only usage.

Local Setup with Hardhat

Use this if you want to compile and test locally with Node.js.

Requirements

• Node.js 18+ and npm (install from https://nodejs.org)

Install and Initialize

Run these commands from the repo root:

npm init -y
npm install --save-dev hardhat
npx hardhat init

Add Contracts

• Copy the folder(s) you want into the contracts/ directory, or
• Move all .sol files into contracts/ and keep the folder structure.

Compile

npx hardhat compile

Run a Script (Optional)

Create a script in scripts/ and run:

npx hardhat run scripts/yourScript.js

Exercises

The 16-Exercises folder contains TODO-based practice files. Start with 01_AddressBook.sol and work in order.

Testing

No automated tests are included. Use Remix or Hardhat to manually deploy and interact.

Contributing

Contributions are welcome for typos, clarity improvements, or new examples. Keep changes small and focused.

License

Add a license file if you plan to distribute or reuse this material.