pragma solidity ^0.4.24;
contract ERC20 {
  function totalSupply() public view returns (uint256);

  function balanceOf(address _who) public view returns (uint256);

  function allowance(address _owner, address _spender)
    public view returns (uint256);

  function transfer(address _to, uint256 _value) public returns (bool);

  function approve(address _spender, uint256 _value)
    public returns (bool);

  function transferFrom(address _from, address _to, uint256 _value)
    public returns (bool);

  event Transfer(
    address indexed from,
    address indexed to,
    uint256 value
  );

  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

interface TokenRecipient {
  function receiveApproval(address _sender, uint256 _value,  bytes _data) external returns (bool ok);
}

library SafeMath {

  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 _a, uint256 _b) internal pure returns (uint256) {
    // Gas optimization: this is cheaper than asserting 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    if (_a == 0) {
      return 0;
    }

    uint256 c = _a * _b;
    assert(c / _a == _b);

    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
    // assert(_b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = _a / _b;
    // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold

    return c;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
    assert(_b <= _a);
    uint256 c = _a - _b;

    return c;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 _a, uint256 _b) internal pure returns (uint256) {
    uint256 c = _a + _b;
    assert(c >= _a);

    return c;
  }

  /**
   * @dev gives square root of given x.
   */
  function sqrt(uint256 x)
      internal
      pure
      returns (uint256 y)
  {
      uint256 z = ((add(x,1)) / 2);
      y = x;
      while (z < y)
      {
          y = z;
          z = ((add((x / z),z)) / 2);
      }
  }

  /**
   * @dev gives square. multiplies x by x
   */
  function sq(uint256 x)
      internal
      pure
      returns (uint256)
  {
      return (mul(x,x));
  }

  /**
   * @dev x to the power of y
   */
  function pwr(uint256 x, uint256 y)
      internal
      pure
      returns (uint256)
  {
      if (x==0)
          return (0);
      else if (y==0)
          return (1);
      else
      {
          uint256 z = x;
          for (uint256 i=1; i < y; i++)
              z = mul(z,x);
          return (z);
      }
  }
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */



/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/issues/20
 * Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20 {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  mapping (address => mapping (address => uint256)) internal allowed;

  uint256 totalSupply_;

  /**
  * @dev Total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(
    address _owner,
    address _spender
   )
    public
    view
    returns (uint256)
  {
    return allowed[_owner][_spender];
  }

  /**
  * @dev Transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_value <= balances[msg.sender]);
    require(_to != address(0));

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * Beware that changing an allowance with this method brings the risk that someone may use both the old
   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amount of tokens to be transferred
   */
  function transferFrom(
    address _from,
    address _to,
    uint256 _value
  )
    public
    returns (bool)
  {
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);
    require(_to != address(0));

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
  }


  function transferContract(address _to, uint256 _value, bytes _data) public
    returns (bool success)
  {
    bool isContract = false;
    // solium-disable-next-line security/no-inline-assembly
    assembly {
      isContract := not(iszero(extcodesize(_to)))
    }
    if (isContract) {
      transfer(_to, _value);
      TokenRecipient receiver = TokenRecipient(_to);
      require(receiver.receiveApproval(msg.sender, _value, _data));//call another contract
    }
    return isContract;
  }

  /*
  function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) {
      TokenRecipient spender = TokenRecipient(_spender);
      if (approve(_spender, _value)) {
          spender.receiveApproval(msg.sender, _value, this, _extraData);
          return true;
      }
  }
  */

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(
    address _spender,
    uint256 _addedValue
  )
    public
    returns (bool)
  {
    allowed[msg.sender][_spender] = (
      allowed[msg.sender][_spender].add(_addedValue));
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseApproval(
    address _spender,
    uint256 _subtractedValue
  )
    public
    returns (bool)
  {
    uint256 oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue >= oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
contract BurnableToken is StandardToken {

  event Burn(address indexed burner, uint256 value);

  /**
   * @dev Burns a specific amount of tokens.
   * @param _value The amount of token to be burned.
   */
  function burn(uint256 _value) public {
    _burn(msg.sender, _value);
  }

  /**
   * @dev Burns a specific amount of tokens from the target address and decrements allowance
   * @param _from address The address which you want to send tokens from
   * @param _value uint256 The amount of token to be burned
   */
  function burnFrom(address _from, uint256 _value) public {
    require(_value <= allowed[_from][msg.sender]);
    // Should https://github.com/OpenZeppelin/zeppelin-solidity/issues/707 be accepted,
    // this function needs to emit an event with the updated approval.
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    _burn(_from, _value);
  }

  function _burn(address _who, uint256 _value) internal {
    require(_value <= balances[_who]);
    // no need to require value <= totalSupply, since that would imply the
    // sender's balance is greater than the totalSupply, which *should* be an assertion failure

    balances[_who] = balances[_who].sub(_value);
    totalSupply_ = totalSupply_.sub(_value);
    emit Burn(_who, _value);
    emit Transfer(_who, address(0), _value);
  }
}


contract PCToken is BurnableToken {

//  using SafeMath for uint256;
  // metadata
  string public constant name = "PetCraftToken";
  string public constant symbol = "PCTOKEN";
  uint256 public constant decimals = 18;
  string public version = "1.0";

  // deposit address
  address public inGameRewardAddress;
  address public userGrowPoolAddress;
  address public developerAddress;

  // constructor
  constructor(address _financeContract) public {
      require(_financeContract != address(0));
      inGameRewardAddress = _financeContract;
      userGrowPoolAddress = msg.sender; 
      developerAddress = msg.sender;

      balances[inGameRewardAddress] = 300000000 * 10**uint(decimals);
      balances[userGrowPoolAddress] = 0;
      balances[developerAddress] = 1200000000 * 10**uint(decimals);
      totalSupply_ = balances[inGameRewardAddress] + balances[userGrowPoolAddress] + balances[developerAddress];
  }
}