contract FixedSupplyToken is ERC20Interface {
      string public constant symbol = "EHD";
      string public constant name = "以太钻石"; 
      uint8 public constant decimals = 18; 
      uint256 _totalSupply = 55000000000000000000000000; 


      address public owner;


      mapping(address => uint256) balances;


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


      modifier onlyOwner() {
          if (msg.sender != owner) {
              throw;
          }
          _;
      }


      function FixedSupplyToken() {
          owner = msg.sender;
          balances[owner] = _totalSupply;
      }

      function totalSupply() constant returns (uint256 totalSupply) {
          totalSupply = _totalSupply;
      }


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


      function transfer(address _to, uint256 _amount) returns (bool success) {
          if (balances[msg.sender] >= _amount 
              && _amount > 0
              && balances[_to] + _amount > balances[_to]) {
              balances[msg.sender] -= _amount;
              balances[_to] += _amount;
              Transfer(msg.sender, _to, _amount);
              return true;
          } else {
              return false;
          }
      }


      function transferFrom(
          address _from,
          address _to,
          uint256 _amount
      ) returns (bool success) {
          if (balances[_from] >= _amount
              && allowed[_from][msg.sender] >= _amount
              && _amount > 0
              && balances[_to] + _amount > balances[_to]) {
              balances[_from] -= _amount;
              allowed[_from][msg.sender] -= _amount;
              balances[_to] += _amount;
              Transfer(_from, _to, _amount);
              return true;
          } else {
              return false;
          }
      }


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

      //返回被允许转移的余额数量
      function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
          return allowed[_owner][_spender];
      }
  }
function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
}

//返回被允许转移的余额数量