Trending questions in Blockchain

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1 answer

How to efficiently hash (SHA 256) in golang data where only the last few bytes changes

You can try the following examples on ...READ MORE

Jun 27, 2018 in Blockchain by aryya
• 7,460 points
5,692 views
0 votes
1 answer

How to fix browser/IERC20.sol:4:53: Warning: This declaration shadows an existing declaration

I believe the issue is the reuse ...READ MORE

Oct 1, 2018 in Blockchain by slayer
• 29,370 points
1,549 views
0 votes
1 answer

Go build fail, fatal error: rocksdb/c.h

I followed here and it is done. https://github.com/openblockchain/obc-peer/issues/885 Configure ...READ MORE

Sep 17, 2018 in Blockchain by slayer
• 29,370 points
2,122 views
+1 vote
3 answers

Pass all .dat files in folder to function

os.listdir(path) return names, not fullpaths change parseBlockFile(file) to fullpath = os.path.join(path,file) if os.path.isfile(fullpath) ...READ MORE

Sep 5, 2018 in Blockchain by Saygum
2,526 views
0 votes
1 answer

Ethereum serpent version conflict error.

Upgrade to the lastest version of ethereum-serpent ...READ MORE

Oct 24, 2018 in Blockchain by Omkar
• 69,220 points
487 views
+1 vote
1 answer

Solidity: Sending ERC20 Tokens

You can try this code transferTokensTo: function(contract, address_from, ...READ MORE

Sep 26, 2018 in Blockchain by slayer
• 29,370 points
1,643 views
0 votes
1 answer

Not able send ether to my smart contract's address

It turns out that you need to create ...READ MORE

Sep 25, 2018 in Blockchain by slayer
• 29,370 points
1,708 views
0 votes
1 answer

Python Script to pull data from Blockchain JSON

Try this: print r.json()['address'],' has ', r.json()['n_tx'], 'tr ...READ MORE

Sep 14, 2018 in Blockchain by digger
• 26,740 points
2,174 views
0 votes
1 answer

Ethereum generating genesis Python Syntax

print in python3 is a method not a ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
• 69,220 points
1,035 views
0 votes
1 answer

sellprice and buyprice fixing in smart contract.

It is due to the fact you ...READ MORE

Oct 17, 2018 in Blockchain by Christine
• 15,790 points
681 views
0 votes
1 answer

Poloniex C# API - get trades

Outputting the Trade will just show you ...READ MORE

Sep 25, 2018 in Blockchain by digger
• 26,740 points
1,620 views
0 votes
1 answer

How can I inject and use this javascript library (web3) with JavascriptCore

The web3.js library has dependencies on bignumber.js and crypto-js.js (See dependencies here). You will ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
• 69,220 points
1,043 views
0 votes
1 answer

Where is the geth.exe in the Ethereum mist?

In Windows, you will find geth.exe in ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
• 69,220 points
948 views
0 votes
1 answer

What happens to Ether in a smart contract after selfdestruct?

selfdestruct takes one argument an address and then sends all ...READ MORE

Oct 3, 2018 in Blockchain by digger
• 26,740 points
1,249 views
0 votes
1 answer

Cant decode hex sting into decimal. Getting TypeError.

On the line where it shows error, ...READ MORE

Jul 6, 2018 in Blockchain by slayer
• 29,370 points
5,085 views
0 votes
1 answer

403 forbidden error coinbase api

I had a similiar issue connecting this API, ...READ MORE

Aug 28, 2018 in Blockchain by digger
• 26,740 points
2,779 views
0 votes
1 answer

Solidity how to solve “Error Encoding arguments ” error while using create button?

When you pass multiple arguments, you need ...READ MORE

Jul 30, 2018 in Blockchain by slayer
• 29,370 points
4,054 views
0 votes
1 answer

Solidity different token price

Yes you can do this by modifying ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
• 69,220 points
978 views
0 votes
2 answers

Warning: Using contract member “balance” inherited from the address type is deprecated. Solidity

Alternatively you could assign this to a local variable ...READ MORE

Oct 3, 2018 in Blockchain by Rustom
1,306 views
0 votes
1 answer

Nethereum C# Unit Test GetTransactionCount

You have already made the test async ...READ MORE

Sep 26, 2018 in Blockchain by slayer
• 29,370 points
1,475 views
0 votes
1 answer

Solidity: How can I return a list of user-defined function?

You can do it with something like ...READ MORE

Sep 26, 2018 in Blockchain by digger
• 26,740 points
1,474 views
0 votes
1 answer

Sending hash in function parameter

I am developing a smart contract using ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
• 69,220 points
955 views
0 votes
1 answer

Why estimateGas always returns null or zero?

The Web3 API uses error first style callbacks. Your ...READ MORE

Sep 28, 2018 in Blockchain by digger
• 26,740 points
1,383 views
0 votes
1 answer

How can I create an online wallet without any 3rd party API on my PHP server?

With any approach, you need a bitcoin ...READ MORE

Aug 30, 2018 in Blockchain by Perry
• 17,100 points
2,656 views
0 votes
1 answer

BitcoinJ generate address from private key

Convert string private key into bytes[]: ECKey key = ...READ MORE

Sep 4, 2018 in Blockchain by slayer
• 29,370 points
2,415 views
0 votes
1 answer

Solidity mocha : address is not a contract error

Try the following: // Initialize contract variable with ...READ MORE

Oct 1, 2018 in Blockchain by digger
• 26,740 points
1,241 views
0 votes
1 answer

How to generate Bitcoin address in Ruby?

In your generate_address_from_public_key_hash method, the checksum should be over ...READ MORE

Aug 22, 2018 in Blockchain by slayer
• 29,370 points
2,950 views
0 votes
1 answer

Truffle tests not running after truffle init

This was a bug. They've fixed it. ...READ MORE

Sep 11, 2018 in Blockchain by Christine
• 15,790 points
2,086 views
0 votes
1 answer

Solidity invalid opcode error

In the for loop, your indexing going ...READ MORE

Aug 16, 2018 in Blockchain by slayer
• 29,370 points
3,208 views
0 votes
1 answer

How to convert byte array to hex string?

You are missing the padding in the ...READ MORE

Aug 17, 2018 in Blockchain by slayer
• 29,370 points
3,162 views
0 votes
1 answer

Handling UI when a trasaction is in pending (MetaMask)

You need to use the state of ...READ MORE

Oct 3, 2018 in Blockchain by digger
• 26,740 points
1,130 views
0 votes
1 answer

Getting the length of public array variable (getter)

The calling contract will need the ABI ...READ MORE

Sep 24, 2018 in Blockchain by digger
• 26,740 points
1,514 views
0 votes
1 answer

How to allow request from host machine and deny from other machine, using ethereum in docker?

You can restrict access to the port ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
• 69,220 points
846 views
0 votes
1 answer

Go- Chaincode function to display struct values

Try this func (t *SimpleChaincode) setDetails(stub shim.ChaincodeStubInterface, args ...READ MORE

Sep 19, 2018 in Blockchain by digger
• 26,740 points
1,706 views
0 votes
1 answer

Creating an account with web3.js v0.2.6

The answer is let a=web3.personal.newAccount('!@superpassword') H ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
• 69,220 points
813 views
0 votes
1 answer

Intl.NumberFormat() does not show the Bitcoin Ƀ Symbol

According to bitcoin.it (https://en.bitcoin.it/wiki/Bitcoin_symbol), The ISO 4217 currency code for ...READ MORE

Aug 27, 2018 in Blockchain by slayer
• 29,370 points
2,667 views
0 votes
1 answer

How to use Coinbase send_money API?

<?php require_once(dirname(__FILE__) . '/../lib/Coinbase.php'); // Create an application at ...READ MORE

Sep 12, 2018 in Blockchain by slayer
• 29,370 points
1,975 views
0 votes
1 answer

I am not able to change array elements globally

Remove the constant modifier from getArray(). constant functions do not write state ...READ MORE

Oct 9, 2018 in Blockchain by Omkar
• 69,220 points
800 views
+2 votes
1 answer

Composer playground - issue on RHEL

Hey, Renu353. There could be more than ...READ MORE

Sep 24, 2018 in Blockchain by Omkar
• 69,220 points
1,355 views
0 votes
1 answer

Web is not injected by metamask

You need to do import the Web3 ...READ MORE

Oct 3, 2018 in Blockchain by slayer
• 29,370 points
1,036 views
0 votes
1 answer

How to make a class that fits Blockchain.info Json?

Hey, I found a simple solution for ...READ MORE

Sep 18, 2018 in Blockchain by digger
• 26,740 points
1,681 views
0 votes
1 answer

Bitcoinj send payment from a wallet

The problem actually was with the input ...READ MORE

Sep 6, 2018 in Blockchain by slayer
• 29,370 points
2,144 views
0 votes
2 answers

Creating a private/public key with 64 characters that are already known using bitcoinjs

//public-key var address = eckey.getBitcoinAddress().toString(); var privateKeyBytesCompressed = privateKeyBytes.slice(0); ...READ MORE

Sep 10, 2018 in Blockchain by Misty
1,930 views
+6 votes
3 answers

Why don't we consider Git as a Blockchain?

Blockchain is not just any chain of any blocks. Blockchain is when there ...READ MORE

Sep 7, 2018 in Blockchain by Rowski
3,622 views
0 votes
1 answer

Transfer the gas value of contract to my own address

Works fine for me: pragma solidity ^0.4.0; contract Test ...READ MORE

Oct 10, 2018 in Blockchain by Omkar
• 69,220 points
654 views
0 votes
1 answer

Python request module for bitcoin json rpc

This should work: #!/usr/bin/env python import getpass import json import requests ...READ MORE

Aug 28, 2018 in Blockchain by digger
• 26,740 points
2,503 views
0 votes
1 answer

Error when Installing Ethereum: Package 'ethereum' has no installation candidate

It seems that there is a compatibility ...READ MORE

Oct 3, 2018 in Blockchain by digger
• 26,740 points
938 views
0 votes
1 answer

Calling functions from other contracts solidity

This code worked for me: pragma solidity ^0.4.2; contract ...READ MORE

Sep 17, 2018 in Blockchain by digger
• 26,740 points
1,610 views
+5 votes
1 answer

What are the programming languages I should know to become a Blockchain Developer?

Well, what programming language you have to ...READ MORE

Sep 25, 2018 in Blockchain by digger
• 26,740 points
1,060 views
0 votes
1 answer

How to choose which function is called first in Node Js

You can do something like: infuraProvider.getBlockNumber().then(function(blockNumber) { ...READ MORE

Oct 8, 2018 in Blockchain by Omkar
• 69,220 points
697 views