contract StandardToken is Token {

    /**
     * Reviewed:
     * - Interger overflow = OK, checked
     */

    function transfer(address _to, uint256 _value) returns (bool success) {
      //Default assumes totalSupply can't be over max (2^256 - 1).
      //If your token leaves out totalSupply and can issue more tokens as time goes on, you need to check if it doesn't wrap.
      //Replace the if with this one instead.
      if (balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]) {
        //if (balances[msg.sender] >= _value && _value > 0) {
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
      } else { return false; }
    }

    function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {
        //same as above. Replace this line with the following if you want to protect against wrapping uints.
      if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && balances[_to] + _value > balances[_to]) {
        //if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0) {
        balances[_to] += _value;
        balances[_from] -= _value;
        allowed[_from][msg.sender] -= _value;
        Transfer(_from, _to, _value);
        return true;
      } else { return false; }
    }

    function balanceOf(address _owner) constant returns (uint256 balance) {
      return balances[_owner];
    }

    function approve(address _spender, uint256 _value) returns (bool success) {
      allowed[msg.sender][_spender] = _value;
      Approval(msg.sender, _spender, _value);
      return true;
    }

    function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
      return allowed[_owner][_spender];
    }

    mapping (address => uint256) balances;

    mapping (address => mapping (address => uint256)) allowed;

    uint256 public totalSupply;

}
/**
 * ERC 20 token
 *
 * https://github.com/ethereum/EIPs/issues/20
 */
function transfer(address _to, uint256 _value) returns (bool success) {
      //Default assumes totalSupply can't be over max (2^256 - 1).
      //If your token leaves out totalSupply and can issue more tokens as time goes on, you need to check if it doesn't wrap.
      //Replace the if with this one instead.
      if (balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]) {
        //if (balances[msg.sender] >= _value && _value > 0) {
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
      } else { return false; }
    }
/**
 * Reviewed:
 * - Interger overflow = OK, checked
 */