pragma solidity ^0.4.11;

library SafeMath {
  function mul(uint a, uint b) internal returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint a, uint b) internal returns (uint) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

  function sub(uint a, uint b) internal returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function add(uint a, uint b) internal returns (uint) {
    uint c = a + b;
    assert(c >= a);
    return c;
  }

  function max64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal constant returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal constant returns (uint256) {
    return a < b ? a : b;
  }

  function assert(bool assertion) internal {
    if (!assertion) {
      throw;
    }
  }
}

contract ERC20Basic {
  uint public totalSupply;
  function balanceOf(address who) constant returns (uint);
  function transfer(address to, uint value);
  event Transfer(address indexed from, address indexed to, uint value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender) constant returns (uint);
  function transferFrom(address from, address to, uint value);
  function approve(address spender, uint value);
  event Approval(address indexed owner, address indexed spender, uint value);
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint;

  mapping(address => uint) balances;

  modifier onlyPayloadSize(uint size) {
     if(msg.data.length < size + 4) {
       throw;
     }
     _;
  }

  function transfer(address _to, uint _value) onlyPayloadSize(2 * 32) {
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    Transfer(msg.sender, _to, _value);
  }

  function balanceOf(address _owner) constant returns (uint balance) {
    return balances[_owner];
  }

}

contract StandardToken is BasicToken, ERC20 {

  mapping (address => mapping (address => uint)) allowed;

  function transferFrom(address _from, address _to, uint _value) onlyPayloadSize(3 * 32) {
    var _allowance = allowed[_from][msg.sender];
    balances[_to] = balances[_to].add(_value);
    balances[_from] = balances[_from].sub(_value);
    allowed[_from][msg.sender] = _allowance.sub(_value);
    Transfer(_from, _to, _value);
  }


  function approve(address _spender, uint _value) {
    if ((_value != 0) && (allowed[msg.sender][_spender] != 0)) throw;
    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
  }

  function allowance(address _owner, address _spender) constant returns (uint remaining) {
    return allowed[_owner][_spender];
  }
}

contract EGC is StandardToken{
    string public constant name = "ExchangeGoodsChain";
    string public constant symbol = "EGC";
    uint public constant decimals = 18;
    string public constant version = "1.0";
    // uint public constant totalNumber =13*(10**8)*(10**decimals);
    //all coin is under this host
    address public host;
    //can make token start
    address public owner;

    modifier onlyOwner{
      if(msg.sender != owner) throw;
      _;
    } 

    //events
    event InitHostBalance(address _host,uint number);

    function EGC(){
        owner = msg.sender;
        //set total number of token
        totalSupply = 13*(10**8)*(10**decimals);
    }

    function initToken(address _host) onlyOwner{
      //set all tokens to _host
      if(_host==0x0) throw;
      host = _host;
      balances[host] = balances[host].add(totalSupply);
      InitHostBalance(host,totalSupply);
    }

    function changeOwner(address newOwner) onlyOwner{
      owner = newOwner;
    }

    //refuse  transactions by eth
    function () payable{
        throw;
    }
    
    function kill() onlyOwner{
        selfdestruct(owner);
    }
}