var {Web3} = require('web3')
var web3 = new Web3('INFURA_API_KEY')
var privateKey = 'YOUR PRIVATE KEY'
var account = web3.eth.accounts.privateKeyToAccount(privateKey)
web3.eth.accounts.wallet.add(account)
web3.eth.defaultAccount = account.address
var abi = /[CONTRACT ABI 여기에 넣기]/
var c_address = 'CONTRACT ADDRESS 여기에 넣기'
var contract = new web3.eth.Contract(abi, c_addr)
contract.methods.a().call().then(console.log)
var tx = {from : account.address, to : c_address , gas : 300000, gasPrice : 3000000, data : contract.methods.함수이름(input 값).encodeABI()}
var signPromise = web3.eth.accounts.signTransaction(tx, account.privateKey)
signPromise.then((signedTx)=> {var sentTx = web3.eth.sendSignedTransaction(signedTx.raw || signedTx.rawTransaction); sentTx.on("receipt", receipt=> {console.log(receipt)})})
