VRC-20 Contract Standard

VRC-20 is a set of contract standards for the issuance of token assets, that is, contracts written in compliance with this standard are considered to be a VRC-20 contract. When various wallets and exchanges are docking the assets of the VRC-20 contract, from this set of contract standards, we can know which functions and events the contract defines, so as to facilitate the docking.

Optional
Token name

string public name = "VisionEuropeRewardCoin";

Token abbreviation

string public symbol = "VTK";

Token accuracy

uint8 public decimals = 6;

Required items

contract VRC20 {
    function totalSupply() constant returns (uint theTotalSupply);
    function balanceOf(address _owner) constant returns (uint balance);
    function transfer(address _to, uint _value) returns (bool success);
    function transferFrom(address _from, address _to, uint _value) returns (bool success);
    function approve(address _spender, uint _value) returns (bool success);
    function allowance(address _owner, address _spender) constant returns (uint remaining);
    event Transfer(address indexed _from, address indexed _to, uint _value);
    event Approval(address indexed _owner, address indexed _spender, uint _value);
}

totalSupply()
This method returns the total issuance of the token.

balanceOf(address _owner)
This method returns the token balance of the query account.

transfer(address _to, uint _value)
This method is used to transfer the token from the smart contract address to the specified account.

approve(address _spender, uint _value)
This method is used to authorize a third party (such as a DAPP contract) to transfer the token from the account of the token owner.

transferFrom(address _from, address _to, uint _value)
This method allows a third party to transfer the token from the account of the token owner. It needs to be used in conjunction with the approve() method.

allowance(address _owner, address _spender)
This method is used to query the balance of the token of the query account that can be transferred by a third party.

Event function
When the token is successfully transferred, the Transfer event will be triggered.

event Transfer(address indexed _from, address indexed _to, uint256 _value)

When the approve() method is successfully called, the Approval event will be triggered.

event Approval(address indexed _owner, address indexed _spender, uint256 _value)