use_questos

Use Questos

Due to the compatibility to Ethereum there are many possibilities to use the Questos network. Here you can find an overview that is still being expanded.

One of the most significant Ethereum tokens is known as ERC-20. ERC-20 has emerged as the technical standard; it is used for all smart contracts on the Ethereum blockchain for token implementation and provides a list of rules that all Ethereum-based tokens must follow.

ERC-20 is similar, in some respects, to bitcoin, Litecoin, and any other cryptocurrency; ERC-20 tokens are blockchain-based assets that have value and can be sent and received. The primary difference is that instead of running on their own blockchain, ERC-20 tokens are issued on the Ethereum network.

This example shows how to create your own token on the Questos network. It is an example of a QRX-20 (ERC-20) token only.

pragma solidity ^0.4.8;
// ERC Token Standard #20 Interface
// https://github.com/ethereum/EIPs/issues/20

contract ERC20Interface {
    // Get the total token supply
    function totalSupply() constant returns (uint256 totalSupply);
 
    // Get the account balance of another account with address _owner
    function balanceOf(address _owner) constant returns (uint256 balance);
 
    // Send _value amount of tokens to address _to
    function transfer(address _to, uint256 _value) returns (bool success);
 
    // Send _value amount of tokens from address _from to address _to
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
 
    // Allow _spender to withdraw from your account, multiple times, up to the _value amount.
    // If this function is called again it overwrites the current allowance with _value.
    // this function is required for some DEX functionality
    function approve(address _spender, uint256 _value) returns (bool success);
 
    // Returns the amount which _spender is still allowed to withdraw from _owner
    function allowance(address _owner, address _spender) constant returns (uint256 remaining);
 
    // Triggered when tokens are transferred.
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
 
    // Triggered whenever approve(address _spender, uint256 _value) is called.
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
 
contract FixedSupplyToken is ERC20Interface {
    string public constant symbol = "FIXED";
    string public constant name = "Example Fixed Supply Token";
    uint8 public constant decimals = 18;
    uint256 _totalSupply = 1000000;
    
    // Owner of this contract
    address public owner;
 
    // Balances for each account
    mapping(address => uint256) balances;
 
    // Owner of account approves the transfer of an amount to another account
    mapping(address => mapping (address => uint256)) allowed;
 
    // Functions with this modifier can only be executed by the owner
    modifier onlyOwner() {
        if (msg.sender != owner) {
            throw;
        }
        _;
    }
 
    // Constructor
    function FixedSupplyToken() {
        owner = msg.sender;
        balances[owner] = _totalSupply;
    }
 
    function totalSupply() constant returns (uint256 totalSupply) {
        totalSupply = _totalSupply;
    }
 
    // What is the balance of a particular account?
    function balanceOf(address _owner) constant returns (uint256 balance) {
        return balances[_owner];
    }
 
    // Transfer the balance from owner's account to another account
    function transfer(address _to, uint256 _amount) returns (bool success) {
        if (balances[msg.sender] >= _amount 
            && _amount > 0
            && balances[_to] + _amount > balances[_to]) {
            balances[msg.sender] -= _amount;
            balances[_to] += _amount;
            Transfer(msg.sender, _to, _amount);
            return true;
        } else {
            return false;
        }
    }
 
    // Send _value amount of tokens from address _from to address _to
    // The transferFrom method is used for a withdraw workflow, allowing contracts to send
    // tokens on your behalf, for example to "deposit" to a contract address and/or to charge
    // fees in sub-currencies; the command should fail unless the _from account has
    // deliberately authorized the sender of the message via some mechanism; we propose
    // these standardized APIs for approval:
    function transferFrom(
        address _from,
        address _to,
        uint256 _amount
    ) returns (bool success) {
        if (balances[_from] >= _amount
            && allowed[_from][msg.sender] >= _amount
            && _amount > 0
            && balances[_to] + _amount > balances[_to]) {
            balances[_from] -= _amount;
            allowed[_from][msg.sender] -= _amount;
            balances[_to] += _amount;
            Transfer(_from, _to, _amount);
            return true;
        } else {
            return false;
        }
    }
 
    // Allow _spender to withdraw from your account, multiple times, up to the _value amount.
    // If this function is called again it overwrites the current allowance with _value.
    function approve(address _spender, uint256 _amount) returns (bool success) {
        allowed[msg.sender][_spender] = _amount;
        Approval(msg.sender, _spender, _amount);
        return true;
    }
 
    function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }
}
  • use_questos.txt
  • Last modified: 2021/05/19 08:48
  • by questos