contract owned { address public owner; function owned() { owner = msg.sender; } modifier onlyOwner { if (msg.sender != owner) throw; _ } function transferOwnership(address newOwner) onlyOwner { owner = newOwner; } } contract tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData); } contract MyToken is owned { /* Public variables of the token */ string public name; string public symbol; string public version; uint8 public decimals; uint256 public totalSupply; address public minter; /* This creates an array with all balances */ mapping (address => uint256) public balanceOf; mapping (address => mapping (address => uint256)) public allowance; mapping (address => mapping (address => uint256)) public spentAllowance; /* This generates a public event on the blockchain that will notify clients */ event Transfer(address indexed from, address indexed to, uint256 value); /* Initializes contract with initial supply tokens to the creator of the contract */ function MyToken( uint256 initialSupply, string tokenName, uint8 decimalUnits, string tokenSymbol, string versionOfTheCode, address initMinter ) { 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 version = versionOfTheCode; minter = initMinter; } /* Send coins */ function transfer(address _to, uint256 _value) { if (balanceOf[msg.sender] < _value) throw; // Check if the sender has enough if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows balanceOf[msg.sender] -= _value; // Subtract from the sender balanceOf[_to] += _value; // Add the same to the recipient Transfer(msg.sender, _to, _value); // Notify anyone listening that this transfer took place } /* Allow another contract to spend some tokens in your behalf */ function approveAndCall(address _spender, uint256 _value, bytes _extraData) returns (bool success) { allowance[msg.sender][_spender] = _value; tokenRecipient spender = tokenRecipient(_spender); spender.receiveApproval(msg.sender, _value, this, _extraData); return true; } /* A contract attempts to get the coins */ function transferFrom(address _from, address _to, uint256 _value) returns (bool success) { if (balanceOf[_from] < _value) throw; // Check if the sender has enough if (balanceOf[_to] + _value < balanceOf[_to]) throw; // Check for overflows if (spentAllowance[_from][msg.sender] + _value > allowance[_from][msg.sender]) throw; // Check allowance balanceOf[_from] -= _value; // Subtract from the sender balanceOf[_to] += _value; // Add the same to the recipient spentAllowance[_from][msg.sender] += _value; Transfer(_from, _to, _value); return true; } /* This unnamed function is called whenever someone tries to send ether to it */ function () { throw; // Prevents accidental sending of ether } function changeMinter(address newMinter) onlyOwner { minter = newMinter; } function mintToken(address target, uint256 mintedAmount) { if (msg.sender != minter) throw; balanceOf[target] += mintedAmount; totalSupply += mintedAmount; Transfer(0, owner, mintedAmount); Transfer(owner, target, mintedAmount); } }