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Questions tagged [tokens]

A token is a transferable, divisible object on the blockchain, such as a subcurrency or a prediction market share.

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ERC20- Error encountered during contract execution [Reverted] Transfer Already Created Token

I have created contract on Ropston TestNet which will send any already created tokens. Unfortunately its giving me error Transaction Details Available at: https://ropsten.etherscan.io/tx/...
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Are ERC777 & ERC223 smart contracts superior to ERC20 smart contracts?

I have been reading some articles which claim that ERC223 and ERC777 have all the features of ERC20 plus additional features which makes them a superior contract. If this is the case, why are they not ...
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1answer
20 views

Can ERC20 tokens be traded on other blockchain based decentralized exchange?

I have a quick question to ask from you. can we trade erc20 tokens on decentralized exchange which is built on custom replica of ethereum blockchain or you can say on a fork of ethereum blockchain. ...
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2answers
31 views

ERC standard that allows sending tokens from many origins to one destination in one transaction?

I know that any kind of operation over a token is possible so long as you implement the smart contract that achieves what you desire. For example, a function multisend can be developed that allows ...
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1answer
29 views

Mineable Tokens? Is it possible? If so, how can I make one? [duplicate]

Just wondering if you could make a ethereum token that is mineable. I saw this link, but don't really know about it and i dont know anything about solidity. Can someone please help me? Thanks, ...
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13 views

Error on contract code on ethereum website

I have been trying to make a token, but nothing has worked for me. I tried the code on the ethereum site, but no luck. I get this error: Expected identifier, got 'eth_compileSolidity' constructor() ...
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1answer
14 views

Error creating contracts on Ethereum wallet. Need help [duplicate]

I am trying to create an ERC20 token off of ethereum, but when I put the code in the editor in the ethereum wallet, I get a weird error. It says: "throw" is deprecated in favour of "revert()", "...
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I did the registration but how do I add at least a dollar to start adding notes from Choon. [closed]

I trying to get started changing note's from my Choon account. How do I add money to Ethereum account?
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1answer
17 views

Trigger a smart contract token transfer by a third party

I've created an Ethereum token that could be transfered from user to user. As a next step I would like to write a smart contract that transfers an amount of tokens from user A to user B when a ...
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2answers
23 views

Why can't I catch solidity errors testing with truffle?

I'm testing the ERC20 standard. I try to send a transaction from an account with balance=0, which should throw an error. I'm trying to catch it. In my test function, I'm using the following: ...
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1answer
46 views

REMIX: ParserError: Expected identifier but got 'payable' address payable target

Hello i have the follow contract: https://pastebin.com/dQJY55hs I want add this code tu the code above: constructor(uint _totalSupply) public { totalSupply = _totalSupply; balanceOf[msg....
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1answer
15 views

Refill Ether to account after token transfer

During token creation and token transfer some ethers are used as gas. What is the most efficient way to refill an account with the same amount of ether? So that it doesn't run out of funds(ether). I'm ...
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18 views

Strange output from web3.eth.sign

I am trying to sign a message and when using following web3.eth.sign('0xdatainhex','Addressofaccount',function(err,result){console.log(result)}) I am getting following output: r {_bitField: 0, ...
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0answers
19 views

Possible ERC-20 improvement: Token-specific ENS equivalent

With ENS still providing quite a difficult user experience for the average user, I'm wondering why standards like ERC-20 don't implement a simple mapping allowing people to set names equivalent to ...
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3answers
49 views

infura vs Eth Node [duplicate]

I want to connect web3 services with public Ethereum (main net/test net) to execute my smart contract method. Which is better Infura or to create my on Node? Please suggest.
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0answers
42 views

What is the best secured way to let users interact with a tokens minting function?

I have an ERC20 tokens contract with a function to mint tokens. This function allows users to mint tokens after performing specific actions or activities on a website. If a user performs the action ...
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1answer
27 views

make a contract send a percentage to a specific wallet (always)

how can I make a contract send a percentage to a specific wallet (always)? Example that whenever a transaction is made from this token the 1% go to X wallet. Thank you. Ok felix dolderer thanks for ...
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1answer
16 views

(Truffle) how to call finalize() function after finishing crowdsale

I would like to call token.transferOwnership(msg.sender) after finishing timed crowdsale. So, I inherited FinalizableCrowdsale contract, then override finalization() function to call transferOwnership ...
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2answers
41 views

How does 0x0000000000000000000000000000000000000000 have over $1.5 trillion octillion octillion in tokens? [duplicate]

I looked up 0x0000000000000000000000000000000000000000 on Etherscan, and realized that the address holds a lot in ERC tokens. While the ETH balance (about 7,549 ETH or about $841,000) isn't abnormal, ...
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1answer
26 views

ICO and Token both together

I know we can create a token contract and also we can create a ico contract. Is it possible to create a contract include ICO and Token itself? any idea or example?
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1answer
28 views

how to use toWei() function in web3.js for tokens having 2 decimals?

I am trying to convert amount in wei using web3js function called toWei(). Here is my code: var etherwithdrawamount1=web3Infura.utils.toWei(etherwithdrawamount, 'wei'); Now, the problem is that ...
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1answer
17 views

Is ERC20ImplUpgradeable a Scam?

I found this in GUSD Smart Contract. The ERC20ImplUpgradeable means that the contract can always be changed. And our coin can be stolen whenever they wish without any trace. If this is allowed by ...
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1answer
26 views

Largest possible Supply an Ethereum token that can be created?

What is the largest possible token supply an ERC-20 that can be created?
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1answer
17 views

Ethereum Smart Contract deployed token not showing

pragma solidity ^0.4.24; contract owned { address public owner; function owned() public { owner = msg.sender; } modifier onlyOwner { require(msg.sender == owner); ...
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1answer
29 views

Static Analysis raised 9 warning(s) that requires your attention. Click here to show the warning(s)

I receive these warnings in REMIX so the question is: Can I compile my contract and then verify it regardless of these warnings? pragma solidity ^0.4.25; library SafeMath { function mul(uint256 a,...
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4answers
436 views

Must a Solidity developer know the private keys to the wallet that is tied to a token contract?

To deploy a token contract, there must be a wallet address, am I right? Thus, must the coder be managing the wallet (with its private keys) that is used? I'm looking at the scenario where what if ...
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2answers
37 views

What are the use cases of tokens? How they are different than ethers?

I am searching for the ERC20. From what I found is that , tokens allow us to have our coins based on smart contracts. But I am little bit confused about the use cases of tokens? When I should use them ...
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1answer
34 views

Error in creating instance of deployed contract using truffle console

I deployed Token and Crowdsale contract in separate migration files. During Migration, there was no error. Migration logs are share: Running migration: 2_deploy_token.js Deploying DappToken... ......
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2answers
15 views

What are the difference between _from, _spender and _to address in Ethereum in Solidity?

What are the difference between _from, _spender and _to address in these functions below? function transferFrom(address _from, address _to, uint256 _value) public{/*...*/} function approve(address ...
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1answer
24 views

Issue with smart contract payable function

So I have a ERC20 token smart contract and a timelock contract. Everytime I call the Deposit function on the timelock contract I get the error "The constructor should be payable if you send value". ...
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1answer
33 views

Why do we have to “deposit” into a decentralized exchange?

On a centralized exchange (like coinbase), I understand why we have to deposit money into it in order to trade. But about decentralized exchange, as I've read about, it has some kinds of "atomic swap"...
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1answer
20 views

Best practices on handling both Ξ and tokens

I'm writing a contract which handles both Ξ and ERC20 tokens. I know that many dApps use WETH and I understand what it does, but I'm not sure if it was integrated because that's the only way to ...
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2answers
70 views

Can you send a token and get ether back?

If a user sends a token, let's call it ABC, to the contract that issued that token, can the contract send back ether to the user?
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1answer
15 views

Ethereum Node I want to export transactions from a token

I have an Ethereum node running and I am wanting to export transaction history for a specific ERC20 token to a local database every 10 minutes. Does anyone have any suggestions on how they would do ...
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1answer
83 views

Time Lock and vesting smart contract

I would like to create a smart contract that will take care of locking and/or vesting funds to several beneficiaries (inputted by the owner of the smart contract). The funds that it will vest and lock ...
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1answer
27 views

how to get Token_Id from ERC721 smart contract

How do I retriever Token_Id of cryptokitties from ERC721 Smart contract Smart contract address : https://etherscan.io/address/0x06012c8cf97bead5deae237070f9587f8e7a266d#code
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2answers
31 views

Parity configuration for maximum throughput

What’s the recommended approach for configuring a private ethereum network using Parity to achieve the highest possible transaction throughput? Which is theoretically around 1000 TPS. Let’s say my ...
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1answer
57 views

Upcoming Ethereum hard fork and ERC-20 token as fiat money

The ethereum network may face a new hard fork with the release of Ethereum 2.0 (scalability fixes) Is it true that we might have two parallel ethereum networks each running a different consensus ...
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0answers
45 views

Calculating gas needed to transfer tokens

Suppose I have a wallet with erc20 token balance in it and with zero ethereum balance. I need to send tokens to another wallet. But before I need to send some eth to this wallet to pay gas for tokens'...
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1answer
25 views

difference between return and returns

contract Helloworld { uint private simpleInt; function getValue() public view returns (uint) { return simpleInt; } } What is the difference between "return" and "returns", I am a ...
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2answers
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Solidity can't modify block.timestamp due to lvalue xpression

I have a problem regarding modifying block.timestamp. I would like to modify timestamp in my network and change block.timestamp to unix timestamp, but I got an error at modification: TypeError: ...
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1answer
22 views

Contract Inheritence

Let's suppose we created two contracts: Contract A and Contract B. Contract A is inherit by Zeppelin's standard token ERC20 where as Contract B is inherit by contract A. Will contract B be ...
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1answer
30 views

Staking Contracts

Is there an ERC token which can provide staking functions? I have a use case where as a crypto trader I desire to create tokens for issuance in a pool. The members of the pool will purchase the tokens ...
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1answer
33 views

Query a block explorer to return the balance of a specific type of token in an ethereum address? [duplicate]

Is there a block explorer where one can query an address and it outputs the balance of a specific type of token? Is there an example of how this can be done?
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2answers
171 views

How is it possible for 0x0000000000000000000000000000000000000000 to send out ERC-20 tokens?

Isn't 0x0000000000000000000000000000000000000000 a burn address where no one has private key? If that is the case, how can this address send tokens to other addresses? If you look at Etherscan's ERC-...
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1answer
21 views

How to prevent a token from being exchanged freely

Let's say that I have created a token and this is distributed through a smart contract. Let's assume that this token is not on any exchange and whenever a transaction is executed using this token a ...
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1answer
24 views

Implementing function to transact with other ERC-20 tokens in smart contract?

A while back I saw an example contract which allowed users to send any ERC-20 tokens through one of its functions, but I can't seem to find anything about this anywhere anymore. So, what is the ...
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1answer
31 views

Writing contract for airdrop distribution

I have a problem. we have an ico. I would like to use the selfdrop method for airdrop distribution. While the superskynet's ico continued, they also wrote a selfdrop contract. can you tell me how I ...
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1answer
46 views

Can i receive/use an already existing ERC 20 token in a new smart contract?

If i already have an ERC20 tokens created and has basic functionalities of a token sat at contract address A, can i start to develop a new smart contract which can make use of the ERC20 token at ...
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1answer
16 views

Who is transferFrom function sending tokens from?

I'm new to Solidity and see: function transferFrom(address from, address to, uint256 value) onlyOwner returns (bool) { return super.transferFrom(from, to, value); } I mean is "from" here ...