contract JoosToken is ERC20, BasicToken {

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


  
    string public name;                   
    uint8 public decimals;                
    string public symbol;                 
  
    address public owner;

   constructor() public {
        decimals = 18;                            
        totalSupply_ =  2000000000 * 10 ** uint256(decimals);                        
        balances[0xD9d1Cc6A6dbC82Cc1eBd08c1f1f5FAB53E0fF36d] = totalSupply_;             
        name = "Joos Token";                                   
        symbol = "JOOS";                              
        owner = 0xD9d1Cc6A6dbC82Cc1eBd08c1f1f5FAB53E0fF36d;
        Transfer(address(0x0), 0xD9d1Cc6A6dbC82Cc1eBd08c1f1f5FAB53E0fF36d , totalSupply_);

   }
  
   modifier onlyOwner(){
       require(msg.sender == owner);
       _;
   }
    function changeOwner(address _newOwner) public onlyOwner{
       owner = _newOwner;
   }
   /**
   * @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(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    Transfer(_from, _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;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @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];
  }
  

    function() payable public{
        revert();
    }



}
/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
function allowance(address _owner, address _spender) public view returns (uint256) {
  return allowed[_owner][_spender];
}

/**
 * @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.
 */