Created
September 14, 2017 10:18
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just the standard token contract
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pragma solidity ^0.4.13; | |
contract tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData); } | |
contract MyToken { | |
/* Public variables of the token */ | |
string public name; | |
string public symbol; | |
uint8 public decimals; | |
uint256 public totalSupply; | |
/* This creates an array with all balances */ | |
mapping (address => uint256) public balanceOf; | |
mapping (address => mapping (address => uint256)) public allowance; | |
/* This generates a public event on the blockchain that will notify clients */ | |
event Transfer(address indexed from, address indexed to, uint256 value); | |
/* This notifies clients about the amount burnt */ | |
event Burn(address indexed from, uint256 value); | |
/* Initializes contract with initial supply tokens to the creator of the contract */ | |
function MyToken( | |
uint256 initialSupply, | |
string tokenName, | |
uint8 decimalUnits, | |
string tokenSymbol | |
) { | |
balanceOf[msg.sender] = initialSupply; // Give the creator all initial tokens | |
totalSupply = initialSupply; // Update total supply | |
name = tokenName; // Set the name for display purposes | |
symbol = tokenSymbol; // Set the symbol for display purposes | |
decimals = decimalUnits; // Amount of decimals for display purposes | |
} | |
/* Internal transfer, only can be called by this contract */ | |
function _transfer(address _from, address _to, uint _value) internal { | |
require (_to != 0x0); // Prevent transfer to 0x0 address. Use burn() instead | |
require (balanceOf[_from] > _value); // Check if the sender has enough | |
require (balanceOf[_to] + _value > balanceOf[_to]); // Check for overflows | |
balanceOf[_from] -= _value; // Subtract from the sender | |
balanceOf[_to] += _value; // Add the same to the recipient | |
Transfer(_from, _to, _value); | |
} | |
/// @notice Send `_value` tokens to `_to` from your account | |
/// @param _to The address of the recipient | |
/// @param _value the amount to send | |
function transfer(address _to, uint256 _value) { | |
_transfer(msg.sender, _to, _value); | |
} | |
/// @notice Send `_value` tokens to `_to` in behalf of `_from` | |
/// @param _from The address of the sender | |
/// @param _to The address of the recipient | |
/// @param _value the amount to send | |
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) { | |
require (_value < allowance[_from][msg.sender]); // Check allowance | |
allowance[_from][msg.sender] -= _value; | |
_transfer(_from, _to, _value); | |
return true; | |
} | |
/// @notice Allows `_spender` to spend no more than `_value` tokens in your behalf | |
/// @param _spender The address authorized to spend | |
/// @param _value the max amount they can spend | |
function approve(address _spender, uint256 _value) | |
returns (bool success) { | |
allowance[msg.sender][_spender] = _value; | |
return true; | |
} | |
/// @notice Allows `_spender` to spend no more than `_value` tokens in your behalf, and then ping the contract about it | |
/// @param _spender The address authorized to spend | |
/// @param _value the max amount they can spend | |
/// @param _extraData some extra information to send to the approved contract | |
function approveAndCall(address _spender, uint256 _value, bytes _extraData) | |
returns (bool success) { | |
tokenRecipient spender = tokenRecipient(_spender); | |
if (approve(_spender, _value)) { | |
spender.receiveApproval(msg.sender, _value, this, _extraData); | |
return true; | |
} | |
} | |
/// @notice Remove `_value` tokens from the system irreversibly | |
/// @param _value the amount of money to burn | |
function burn(uint256 _value) returns (bool success) { | |
require (balanceOf[msg.sender] > _value); // Check if the sender has enough | |
balanceOf[msg.sender] -= _value; // Subtract from the sender | |
totalSupply -= _value; // Updates totalSupply | |
Burn(msg.sender, _value); | |
return true; | |
} | |
function burnFrom(address _from, uint256 _value) returns (bool success) { | |
require(balanceOf[_from] >= _value); // Check if the targeted balance is enough | |
require(_value <= allowance[_from][msg.sender]); // Check allowance | |
balanceOf[_from] -= _value; // Subtract from the targeted balance | |
allowance[_from][msg.sender] -= _value; // Subtract from the sender's allowance | |
totalSupply -= _value; // Update totalSupply | |
Burn(_from, _value); | |
return true; | |
} | |
} |
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