I am getting the following error - Here is a error screenshot


pragma solidity ^0.4.22;

import "../node_modules/zeppelin-solidity/contracts/token/ERC20/MintableToken.sol";

contract GustavoCoin  {

    string public name = "GUSTAVO COIN";

    string public symbol = "GUS";

    uint8 public decimals = 18;
  constructor() {


pragma solidity ^0.4.22;

import './GustavoCoin.sol';

import '../node_modules/zeppelin-solidity/contracts/crowdsale/emission/MintedCrowdsale.sol';

import '../node_modules/zeppelin-solidity/contracts/crowdsale/validation/TimedCrowdsale.sol';
contract GustavoCoinCrowdsale is TimedCrowdsale, MintedCrowdsale {

    function GustavoCoinCrowdsale


            uint256 _openingTime,

            uint256 _closingTime,

            uint256 _rate,

            address _wallet,

            MintableToken _token



        Crowdsale(_rate, _wallet, _token)

        TimedCrowdsale(_openingTime, _closingTime) {



module.exports = {
  networks: {
      development: {
          host: "", 
          port: 8545, 
          network_id: "*" // Match any network id 

I am follwimg a tutorial from this link.

  • 1
    Please provide the section of code which are relevant to your question - for example the truffle script is missing. Furthermore, your GustavoCoin does not have such function transferOwnership. – Lauri Peltonen Sep 19 '18 at 11:23
  • @LauriPeltonen I have also mentioned link which i'm following! GustavoCoin is a contract name and the given code is related to my question! for more clearance please see the link given there! – Sunanda Sharma Sep 19 '18 at 11:26

The gist used by the tutorial you mentioned defines the contract as

pragma solidity 0.4.19;
import 'zeppelin-solidity/contracts/token/ERC20/MintableToken.sol';

contract GustavoCoin is MintableToken {

MintableToken inherits OpenZeppelin's Ownable, and that's where transferOwnership method can be found. Your code above lacks is MintableToken inheritance.

| improve this answer | |
  • Then what we can do to resolve it? @Utgarda – Sunanda Sharma Sep 19 '18 at 12:15
  • Compare the contract definition line in your code with the gist, make your code look like the example. I.e. add is MintableToken after your contract name. – Utgarda Sep 19 '18 at 12:16

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