contract ERC20Interface {
  uint256 public destorySupply; //销毁数量
  uint256 public totalSupply; //总发行量不变
  function balanceOf(address _addr) public view returns (uint256); //查询地址对应的token
  function transfer(address _to, uint256 _value) public returns (bool); //主动转账
  function transferFrom(address _from, address _to, uint256 _value) public returns (bool); //被动转账
  function approval(address _delegatee, uint256 _value) public returns (bool); //授权
  function allowance(address _owner, address _spender) public view returns (uint256); //查询授权使用的token
  function destory(uint256 _value) public returns (bool); //Token销毁
  function destoryFrom(address _from, uint256 _value) public returns (bool); //授权Token销毁

  event Transfer(address indexed _from, address indexed _to, uint256 _value); //转账事件
  event Approval(address indexed _owner, address indexed _spender, uint256 _value); //授权事件
  event Destory(address indexed _owner, uint256 _value); //销毁事件

}
function approval(address _delegatee, uint256 _value) public returns (bool);
//被动转账