I'm new to solidity. I'm currently getting the following error TransferHelper: TRANSFER_FROM_FAILED from the safeTransferFrom function. Can someone tell me why?
I have a simple ERC721 smart contract used for testing purposes, I was wondering if it is possible to query the token IDs a specific wallet owns in that smart c
i have the abi json file for a contract and i want to use its functions in my smart contract. is there any way to do it? for example i have a contractA.sol and
just started a solidity coding course and ran into this issue with this code: //SPDX-License-Identifier: MIT pragma solidity >=0.6.0; import "./simplestora
The Solidity's mapping not returns an array inside a struct (when call mapping_data(), the data variable is undefined). Just be able to read it from read() func
The openzeppelin codes of ERC20 token give error in deploying directly. Even after flattern the codes, i am unable to select contract MyToken out of many contra
I keep getting this error, Does anyone know the solution? the code its inheriting, function _mint(address to, uint256 tokenId) internal virtual { // req
In the official waffle documentation you may find the next way to implement fixtures: import {expect} from 'chai'; import {loadFixture, deployContract} from 'et
I am new to truffle and I work on blockchain project so when I "migrate" in truffle develop, this error occurs. Why ? I change the version of my compiler by 4.2
I want to build an NFT that I can paid with an ERC-20 token to mint it. I'm using currently the Mumbai testnet on polygon, and I'm using the Dummy ERC20 token t
I understand why it's important that all nodes on the Ethereum mainnet must execute any smart contract function call which changes the internal state of the con
I am trying to write a smart contract and line 1 is bringing up an error : ParserError: Found version pragma, but failed to parse it. Please ensure there is a
I am trying to deploy my SimpleStorage.sol contract to a ganache local chain by making a transaction using python. It seems to have trouble connecting to the ch
I want to declare an array to store my strings as follows. bytes32[3] verifiedResult; verifiedResult = ["verified successfully", "verified failed", "not clear"]
I am in the process of building a dapp for a project. I have one last thing to adjust: detect when a user changes metamask account to reset the state but it doe
I want to declare an array to store my strings as follows. bytes32[3] verifiedResult; verifiedResult = ["verified successfully", "verified failed", "not clear"]
First question so bare with me if it is not very clear, but I'll try my best. I am currently running through a youtube video to test my contract with hardhat, e
I am trying to perform a certain action say like selling a token only when the message sent to a contract is signed by the contract owner. I knew how I would do
If a smart contract has the compiled bytecode for a contract can the first deploy a subsequent contract? According to Ethereum.org: "To deploy a smart contract,
i try to write NFT marketplace and i have problem with reselling items from user that buy item from owner and new, third user. I use next.js + openzeppelin + ha