I'm using the crowdsale contract (https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/crowdsale/Crowdsale.sol). I have deployed a detailedERC20 smart contract. When I send the ether to the crowdsale contract it shows me the following error: SafeERC20: low-level call failed When I use transfer() externally it works fine. computer Environment Ganache-cli ....

Besides writing smart contracts in the browser, I would also like to write my test in this IDE. Any suggestions how to load the truffle files in http://remix.ethereum.org? I appreciate your help! ....

I'm trying to call the storeQueryResults() function of my smart contract in the following way: storeInput: function(event) { var queryResultHandlerinstance; App.contracts.QueryResultHandler.deployed().then(function(instance) { queryResultHandlerinstance = instance; return queryResultHtandlerinstance.storeQueryResults(1, 2, "a", "b", { from: web3.eth.accounts }); }).then(function(result) { alert("success"); }).catch(function(err) { alert(err.message); }); }, }; Then, after confirming the transaction in Metamask, ....

I have an array of strings in my Contract.sol: string[] messages; function getMessage(uint i) constant returns (string) { require(messages.length > i); return messages; } In my app.js, when the page is loaded I want to populate the page with all the strings. The relevant part of how that's done is ....

How can we connect two truffle applications with each other? E.g., if we have two metacoin applications, how can these two communicate with each other? ....

can we directly add the token logo to the token smart-contract so that we can visualize it in Wallets and Exchanges and so that we don’t have to register it in another way Please help erc20 token standard ....

I am Web app developer and exploring the blockchain technology from few months. I want to convert the live centralized WebApp to Decentralized Blockchain application. I know there is a high cost of Inserting data in to blockchain and there is 15 GB of data I want to put into ....

I am mining ArtByte and LiteCoin using a single GTX 1070 GPU. Everywhere on the internet I am reading that such a card can achieve 20+ MH/s. My card only gets as far as 680 khash/s. Am I missing something? How to investigate this issue? For ArtByte I am using: ....

What is the difference between this syntax: beforeEach( async () => { ... }); and this one: beforeEach(async function() { ... }); Thanks ....

I have a .sol contract: contract HelloWorld { string name="TEST"; uint number; function HelloWorld() { } function getName() returns (string) { return name; } function getNumber() returns (uint) { return number; } function setNumber(uint _number) { number = _number; } } And I'm trying to write a test in javascript ....