All Questions

is it possible to use a smart contract of an existing token in ganache for testing ?? that is, I don't have to create my smart contract

Setup a private network with clique at 15 secs block creation. Started with 3 nodes. Then deployed a smart contract (ERC 721) and send two transactions. After about 2 days idling, and no transactions, ...

function () public payable { uint tokens; /// this math isnt safe tokens = msg.value * 10; /// this didnt give us the address we needed address tokenOwner; ...

I tried to build a proof of inclusion for a particular receipt in a block, but I noticed that in some cases, the receipt was serialised together with the partial state root hash after executing this ...

I have the following function enum OptionType {Invalid, Put, Call} function create( uint256 period, uint256 amount, uint256 strike, OptionType optionType ) { .... } When I ...

We are new to crypto. A while ago we created a coin (3DOM coin) with 14,000,000,000 units and stored them in our wallet on myetherwallet.com. We would like to deploy the token now but we do not have ...

My MainCore contract is a contract who sell NFT, and all the sell and buy have a 1% fee for team developper (uint DevelopperCutTotalSupply). I try to implement the ERC-2222 "Funds Distribution ...

I'm currently having issues with contracts in a small project of mine. The issue is as follows: I have a Go client for a Dapp and some Smart Contracts to interact with. I planned a contract (...

I'm looking for a good, simple, effective PHP toolkit to access Ethereum wallets. I am designing a page where participants can contribute Ethereum towards a final goal. I want the page to not just say ...

with any web3 or ethers provider I am getting this error. This is suddently startedoccuring. Noticed it when my hardhat test cases started failing. Is anyone else facing the same and has solution?? ...

I swap ether to some coins and now i cannot swap back those coin to etherum. Probably i bought some scam coin but now my coinbase wallet is showing price against that coin. Is it possible that i can ...

I'm having problems retrieving some data metrics using the Uniswap JS SDK. When I try to query getInputAmount it returns this error: (node:88) UnhandledPromiseRejectionWarning: TypeError: Cannot read ...

I have two contracts, contract A represents Token A, contract B is its own contract. I users to call a contract B function by paying Token A to contract B, as if they were using a payable function, ...

I am trying to connect the output of geth metrics of a local node to Grafana. I am initializing my node using the following geth command: geth --datadir "n1" --nodiscover --networkid "...

As AAVE documentation suggests, there is a deployed version of the protocol on matic/polygon mainnet. However, it does not make any mention of those smart contracts on Mumbai testnet which I need to ...

I've seen the other StackExchange errors but it didn't help me. Untitleded.sol:5:77: ParserError: Expected type name function sendmessage(string message) view public returns(string message, memory) { ...

User storage user = users[msg.sender]; I have a "User" struct: struct User { Deposit[] deposits; uint256 checkpoint; address referrer; uint256[3] levels; uint256 ...

I have s smart contract that holds ERC20 DAI token that needs to be transfer to my wallet. Using javascript web3 side on kovan testnet: const EthereumTx = require('ethereumjs-tx').Transaction const ...

$ geth version Geth Version: 1.10.2-stable Git Commit: 97d11b0187b4695ccf44e3b71b54155fe405a36f Git Commit Date: 20210408 Architecture: amd64 Go Version: go1.16 Operating System: linux GOPATH= GOROOT=...

I downloaded the project from Binance Smart Chain github account and when I say make all, I get the following error.

I'm looking at the code of some smart contracts and I've seen somewhere where the code is something like: if (msg.sender == storage[0x00] & 0xffffffffffffffffffffffffffffffffffffffff) From my ...

I import 10 accounts from ganache to metamask and I give each user's login to my application an address. i want to switch between this address without using metamask i want to change this address ...

So for example, I want to enable my contract 1 week after deployment, thats now() + 1 week, how could I know which block that will be so I can send my clients a countdown to that block with https://...

I just generated new Ethereum account with geth account new Your new account is locked with a password. Please give a password. Do not forget this password. Password: Repeat password: Your new key ...

I am working with pancakeswap and I was following a tutorial which just said that we need to calculated the INIT_HASH and that we can follow this link enter link description here for guidance. The ...

I'm trying to develop a weighted probability selection algorithm on BSC and I think I need an algorithm that can generate a random number within a given range for that. What would be a "good ...

Okay, so obviously I bought a scamcoin, but theres this one guy who still managed to sell it, most likely by using a bot. I want to sell the token as well, the liquidity isn't pulled and I would make ...

I have a 3 nodes quorum network, which I created with the help of quorum maker. I am adding an new account to my first node, so that my first node now has 2 accounts on it. I want to find the public ...

After reading this article ("The Unreasonable Ecological Cost of #CryptoArt" Part 1, Part 2), I'm keen to better understand what are the factors involved in energy consumption by NFTs. The ...

I am trying to pass a default value in solidity but get the following error: "Invalid implicit conversion from enum tlb.Category to enum tlb.Category[] memory requested" Does anybody have an ...

We're currently syncing a Full Archive Node (--gcmode archive --sync full --mainnet) and are experiencing a relatively odd behavior: As you can see, the node seems to "pause" its processing ...

I am new to solidity and have been creating single (both basic and complex) transactions. However, I have a question which I couldn't come up with a solution. How can I create 2 (or more) transactions ...

The question is that the simple organization token is built with basic Open Zeppelin libraries. It doesn’t have a custom implementation. It’s not a whatever protocol. Any reasons to make it ...

What are DeFi Smart Accounts? And how they are different from ethereum accounts? It seems "Smart Accounts" is not exact thing, non-standard within Ethereum ecosystem

On opensea, I converted (wrapped) 1 ETH to 1 WETH, which is equal to 2 x 0.5 WETH = 1 WETH. I then spent 0.5 WETH on 3 items = 1.5 WETH, which is greater than the amount I had. how is this even ...

The normal operation of Ethereum and other blockchains is to Store new transactions in a mempool, Distribute the bucket, and then mine contents into a block picked from the bucket based on priority of ...

I've been hearing a lot about nft and I understand some fundamentals, though I am not 100% clear how would one prove ownership of an NFT token. Does proving NFT ownership requires to pay gas fees?

Im using solidity version 0.5.1(Ik they are vulnabilities in that version). Im getting this erorr saying "Untitleded.sol:5:49: TypeError: Data location must be "memory" for return ...

I am new to the use of blockchain we are building an application where I have the following problem to solve: Users when registering in our system will create a wallet of an ethereum token Be able to ...

I have two functions, called one after another. The first one called creates a new Web3 object and sets it to window.web3: async loadWeb3() { window.addEventListener('load', async () => { ...

Is it possible to detect from the smart contract in solidity if it runs on mainnet or testnet? Or if it runs on ganache? Maybe by getting the network ID? But I'm not sure it's possible from the smart ...

so I have the following function in my smart contract: function proxy(address target, uint value, string memory signature, bytes memory data, uint eta) public returns (bytes32) { callData = ...

Is there any way to disable creation of smart contracts on Hyperledger Besu Private Network for addresses except those that I specify? I want to create private network with zero gas fee, but no one ...

I sent eth to wrong address by accident thru and exchange hitbtc 2. It whats a mistyped attempt so it is considered a "fresh" or unclaimed account. Is there any way around this? if so im up ...

I noticed that the callTokensReceived hook is called when using a few of the ERC777 functions but I am wondering how this could be triggered if an ERC20 token was sent to it? Example (pseudo code): ...

while trying to understand the OpenZeppelin contracts that a contract inheritated from I stumbled unto this line "using Counters for Counters.Counter;" (after the library counters of ...

Assuming I have a device that receives sensor data in C, and I want to make calls to an Ethereum smart contract directly through it, is there a way to use C/C++ for that communication? Something ...

I am trying to deploy bnbstaking.sol for my own project by cloning pancakeswap-farm repository. The farm repository has other contracts of MasterChef, Souschef, CakeToken and SyrupBar. For farming all ...

For the past two days I've been trying to synchronize with Ropsten testnet using the following command in Geth 1.9.25: ./geth --ropsten --rpc --rpcaddr="0.0.0.0" --rpcapi="eth, web3, ...

In a smart contract where the token name and symbol are defined, is unicode supported or should these be ASCII only characters? As below, would it be a valid contract or token symbol? constructor()...