How to create a smart contract on Ethereum with Solidity

Introduction

This tutorial will walk you through the process of creating a simple Ethereum smart contract using Solidity, the programming language for writing Ethereum smart contracts.

Prerequisites

To follow this tutorial, you will need:

Node.js and npm installed on your system
Truffle Suite, a development environment, testing framework, and asset pipeline for Ethereum
Ganache, a personal blockchain simulator for Ethereum

You can install Truffle and Ganache with the npm command:

npm install -g truffle

npm install -g ganache-cli

Project creation

Let's start by creating a new directory for our project and initialize a new Truffle project.

mkdir ethereum-contract

cd ethereum-contract

truffle init

Write the Smart Contract

Let's create a new file called SimpleStorage.sol in the contracts/ directory and add the following code:

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

 contract SimpleStorage {
 uint public data;

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

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

This is a very simple contract that stores an integer and provides two functions, set and get, for changing and getting the value.

Creating the migration file

To deploy the contract on the blockchain, you will need to create a migration file. Create a new file called 2_deploy_contracts.js in the migrations/ directory and add the following code:

const SimpleStorage = artifacts.require("SimpleStorage");

 module.exports = function (deployer) {
 deployer.deploy(SimpleStorage);
 };

Test the contract

Before deploying the contract, we should write some tests of it. Create a new file called simpleStorage.js in the test/ directory and add the following code:

const SimpleStorage = artifacts.require('SimpleStorage');

 contract('SimpleStorage', () => {
 it('should set the value of data variable', async () => {
 const simpleStorage = await SimpleStorage.deployed();
 await simpleStorage.set(10);
 const result = await simpleStorage.get();
 assert(result.toNumber() === 10);
 });
 });

Run the tests with the command:

truffle test

Distribute the contract

Finally, we distribute the contract on our local blockchain using Ganache. Run the command:

ganache-cli

In another terminal, run the migration command:

truffle migrate

Conclusion

Congratulations! You have just written and deployed your first smart contract on Ethereum with Solidity.