Practical 1
Setting up environment
- We need to connect our machine to etherium network.
- To able to do transaction to etherium network we need to pay fees called gas which is distributed to miners
- As buying ether is so expensive we can connect to test network instead of main network for learning purpose.
- So to turn our browser into node for the test network use the metamask extenstion
- get free ethers for sepolia network from these faucets https://faucetlink.to/sepolia
- to use polygon amoy test network use this to add in metamask config
https://support.polygon.technology/support/solutions/articles/82000907114-how-to-add-amoy-network-in-your-wallet-
```text
Network Name: POLYGON AMOY TESTNET
New RPC URL: https://rpc-amoy.polygon.technology/
Chain ID: 80002
Currency Symbol: MATIC
Block Explorer URL: https://www.oklink.com/amoy
```
faucet for polygon amoy : https://faucet.polygon.technology/
- to buy real one
https://medium.com/prepo/setting-up-metamask-and-getting-eth-matic-on-polygon-step-by-step-guide-fd55147a0f05
### Coding
- Use remix.etherium.org IDE
Create a file named `Bank.sol`
```sol
// SPDX-License-Identifier: MIT
pragma solidity 0.8.25;
contract Bank {
int bal;
constructor() public {
bal = 1;
}
function getBalance() view public returns(int) {
return bal;
}
function withdraw(int amt) public {
bal = bal - amt;
}
function deposit(int amt) public {
bal = bal + amt;
}
}
```
- This Bank.sol should be under contracts folder. This file is to be compiled
- Also the file named `deploy_with_web3.ts` should be in scripts folder which will deploy it
```js
// This script can be used to deploy the "Storage" contract using Web3 library.
// Please make sure to compile "./contracts/1_Storage.sol" file before running this script.
// And use Right click -> "Run" from context menu of the file to run the script. Shortcut: Ctrl+Shift+S
import { deploy } from './web3-lib'
(async () => {
try {
const result = await deploy('Bank', [])
console.log(`address: ${result.address}`)
} catch (e) {
console.log(e.message)
}
})()
```
- Now run it like this
- switch to injected metamask instead of remix vm to deploy transaction on our network
### Front end
Instead of running it and using it inside remix lets create a separate front end
- Two things are required ie ABI from compiler section and Address of Bank(not ours) from 'Deploy and run transaction' section.
- Now create html file and type
```html
Document
```