# 4.12. Smart contract language

This chapter provides an overview of smart contract development using Solidity, a high-level, contract-oriented programming language for Ethereum. To enhance the process, we explore integrating Hardhat and Truffle. 

* Hardhat offers a powerful development environment with testing capabilities.
* Truffle streamlines the workflow with tools for compilation, testing, and deployment. 

Solidity's versatility enables smart contract development for various blockchain platforms, including Stargram. Leveraging these tools, developers can create robust and reliable smart contracts on platforms like Stargram Chain.

**Hardhat: Deploy ERC20 Contract**

Step 1. Enter 

Step 2. Run <mark style="background-color:yellow;">npm install</mark> inside the folder

<mark style="background-color:yellow;">$ npm install</mark>

Step 3. Make a copy of <mark style="background-color:yellow;">.env.example to .env</mark>

<mark style="background-color:yellow;">$ cp .env.example .env</mark>

Step 4. Modify <mark style="background-color:yellow;">.env</mark> and fill ONE of the field

<mark style="background-color:yellow;">MNEMONIC=goose easy ivory ...</mark>

<mark style="background-color:yellow;">PRIVATE\_KEY=XXXXXXX</mark>

Step 5. Review Migration Script at <mark style="background-color:yellow;">scripts/deploy-stars-token.js</mark>

&#x20;<mark style="background-color:yellow;">async function main() {</mark>

&#x20;    <mark style="background-color:yellow;">const StarsToken = await hre.ethers.getContractFactory("StarsToken");</mark>

&#x20;    <mark style="background-color:yellow;">const starsToken = await StarsToken.deploy("Starsl Token", "CRT", "1000000000000000000000000");</mark>

&#x20;     <mark style="background-color:yellow;">await starsToken.deployed();</mark>

&#x20;     <mark style="background-color:yellow;">console.log("StarsToken deployed to:", starsToken.address);</mark>

&#x20;<mark style="background-color:yellow;">}</mark>

Step 6. Endpoints setting

By default, the script will be using your local host <mark style="background-color:yellow;">"127.0.0.1"</mark> - If you are not running a localhost, you may leverage the public endpoint <mark style="background-color:yellow;"><http://13.213.36.146:6868/></mark> by making changes to networks in <mark style="background-color:yellow;">hardhat.config.js</mark>, for example:

&#x20;<mark style="background-color:yellow;">networks: {</mark>

&#x20;  <mark style="background-color:yellow;">development: {</mark>

&#x20;    <mark style="background-color:yellow;">url: "<http://localhost:8545>",</mark>

&#x20;    <mark style="background-color:yellow;">accounts: getHDWallet(),</mark>

&#x20;   <mark style="background-color:yellow;">},</mark>

&#x20;  <mark style="background-color:yellow;">testnet: {</mark>

&#x20;    <mark style="background-color:yellow;">url: "<http://13.213.36.146:6868>",</mark>

&#x20;    <mark style="background-color:yellow;">accounts: getHDWallet(),</mark>

&#x20;  <mark style="background-color:yellow;">},</mark>

&#x20;<mark style="background-color:yellow;">},</mark>

Step 7. Deploy Contract

<mark style="background-color:yellow;">npx hardhat run --network \<your-network> scripts/deploy-stars-token.js</mark>

Step 8. Obtain Contract address from the console and input to Metamask

The correct balance will be shown on the Metamask page.

#### Truffle: Deploy ERC20 Contract

Step 1. Enter <mark style="background-color:yellow;">smart-contract-example/truffle</mark> folder

<mark style="background-color:yellow;">$ cd stars-smart-contract-example/truffle</mark>

Step 2. Run <mark style="background-color:yellow;">npm install</mark> inside the folder

<mark style="background-color:yellow;">$ npm install</mark>

Step 3. Make a copy of <mark style="background-color:yellow;">.env.example to .env</mark>

<mark style="background-color:yellow;">$ cp .env.example .env</mark>

Step 4. Modify <mark style="background-color:yellow;">.env</mark> and fill ONE of the fields

<mark style="background-color:yellow;">MNEMONIC=goose easy ivory ...</mark>

<mark style="background-color:yellow;">PRIVATE\_KEY=XXXXXXX</mark>

Step 5. Review Migration Script at

<mark style="background-color:yellow;">migrations/2\_deploy\_stars\_token.js</mark>

<mark style="background-color:yellow;">const StarsToken = artifacts.require("StarsToken");</mark>

<mark style="background-color:yellow;">module.exports = function (deployer) {</mark>

<mark style="background-color:yellow;">deployer.deploy(StarsToken, "Stars Token", "PT", "1000000000000000000000000");</mark>

<mark style="background-color:yellow;">};</mark>

Step 6. Endpoints setting

By default, the script will be using your local host <mark style="background-color:yellow;">"127.0.0.1"</mark> - If you are not running a localhost, you may leverage the public endpoint <mark style="background-color:yellow;"><http://13.213.36.146:6868></mark> by making changes to networks <mark style="background-color:yellow;">ins truffle-config.</mark>j, for example:

<mark style="background-color:yellow;">networks: {</mark>

<mark style="background-color:yellow;">development: {</mark>

<mark style="background-color:yellow;">provider: new HDWalletProvider(getHDWallet(), "<http://127.0.0.1:8545>"), // TODO</mark>

<mark style="background-color:yellow;">network\_id: "\*", // Any network (default: none)</mark>

<mark style="background-color:yellow;">},</mark>

<mark style="background-color:yellow;">testnet: {</mark>

<mark style="background-color:yellow;">provider: new HDWalletProvider(getHDWallet(), "<http://13.213.36.146:6868/>"), // TODO</mark>

<mark style="background-color:yellow;">network\_id: "\*",</mark>

<mark style="background-color:yellow;">skipDryRun: true</mark>

<mark style="background-color:yellow;">},</mark>

<mark style="background-color:yellow;">},</mark>

Step 7. Deploy Contract

<mark style="background-color:yellow;">truffle deployed --network \<your-network></mark>

\ <br>