Category "ethereum"

is two different ERC721 contract can mint same NFT

I'm learning blockchain development recently and I'm implementing ERC721 contract to mint NFT and store the mapping of ownership. What if I deploy a second cont

difference between interface and abstract contract in solidity

I am learning solidity and got to know that interface and abstract are both classes that may contain unused functions. My doubt is: What is the difference betwe

how to adjust ethereum transaction's nonce

In the process of developing the ethereum dapp, I tested the load and there was a nonce error. When building a rawTx, I used web3.getTransactionCount("accountAd

Solidity - Solidity code to Input JSON Description

I want to compile my ethereum HelloWorld.sol smart contract. In all the tutorials is that you do it like this: var solc = require('solc'); var compiledContract

HardHat and Rinkeby ProviderError: Must be authenticated Error

When I run npx hardhat console --network rinkeby accounts = await ethers.provider.listAccounts(); I get Uncaught ProviderError: Must be authenticated! with bel

Nethereum works well in unity editor, but not in android device

I'm using nethereum & unity with infura. (I'm developing an DApp.) I wrote some code for minting new NFT, and tested, and it worked very well. However, afte

deploy solidity contract with c#

I am developing an application on Ethereum blockchain. I use Solidity for contract and Nethereum c# library to connect to the contract. I am somehow new in Ethe

What's the difference between .deploy() vs. .deployed()

I am writing a script for a smart contract that I'll deploy using hardhat. I'm confused on the difference between .deploy() and .deployed(), what does each one

Trouble using python/brownie in WSL

I'm trying to complete the simple collectible NFT tutorial from this freeCodeCamp video. (I'm getting stuck on the script that starts exactly where the link is

Eth, how to call a deposit function from a smart contract

I am working on a project where I need to send ether from an user to a smart contract and from the smart contract to the user. The smart contract is code in Sol

How to find out if an Ethereum address is a contract?

An address in Solidity can be an account or a contract (or other things, such as a transaction). When I have a variable x, holding an address, how can I test if

Ethers.js event listeners - Expected behavior for many getLogs/chainId/blocknumber requests?

I'm building a minting site that requires me to check the number of NFTs minted and display that number in real time to the user. At first I was just making a r

Error when trying to deploy standard OpenZeppelin ERC777 contract to ganache-cli using the brownie framework

I am familiarizing myself with smart contract development using the brownie framework and solidity. To start of I was using the brownie console to deploy some s

Timed Advertisements Solidity Contract

Basically, I'm trying to make the smart contract be able to take exactly 0.05 eth ONLY when the cooldown timer is set to 0. The Dapp I'm creating is a first com

Why is a transaction consuming gas for a public view function?

I deployed the following smart contract on Ropsten ethereum test network and afterwards I tried making a transaction using @alch/alchemy-web3 npm package (Yes,

How is hardhat implicitly knowing deployer address?

I am new to using hardhat and I was trying to figure out how it is working. The documentation seems a little bit fuzzy as there are multiple layers of abstracti

Mobile DApp connecting to Wallet

I've been trying to create simple mobile app prototype (in Flutter) which would allow you to connect to a Wallet and obtains your address(es). I cannot get the

How do I get the balance of an account in Ethereum?

How can I programmatically discover how much ETH is in a given account on the Ethereum blockchain?

How to distinguish ERC20 and ERC721?

How can I differentiate between ERC20 and ERC721? without checking Etherscan

String concatenation in solidity?

How do I concatenate strings in solidity? var str = 'asdf' var b = str + 'sdf' seems not to work.. I looked up the documentation and there is not much mentione