pragma solidity ^0.4.18;


contract Ownable {
  address public owner;
  
  function Ownable() public {
    owner = msg.sender;
  }

  modifier onlyOwner() {
    if (msg.sender != owner) {
      revert();
    }
    _;
  }

  function transferOwnership(address newOwner) public onlyOwner {
    if (newOwner != address(0)) {
      owner = newOwner;
    }
  }

}

contract SafeMath {
  function safeMul(uint a, uint b) internal pure returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeDiv(uint a, uint b) internal pure returns (uint) {
    assert(b > 0);
    uint c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

  function safeSub(uint a, uint b) internal pure returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) internal pure returns (uint) {
    uint c = a + b;
    assert(c>=a && c>=b);
    return c;
  }

  function max64(uint64 a, uint64 b) internal pure returns (uint64) {
    return a >= b ? a : b;
  }

  function min64(uint64 a, uint64 b) internal pure returns (uint64) {
    return a < b ? a : b;
  }

  function max256(uint256 a, uint256 b) internal pure returns (uint256) {
    return a >= b ? a : b;
  }

  function min256(uint256 a, uint256 b) internal pure returns (uint256) {
    return a < b ? a : b;
  }

  /* function assert(bool assertion) internal { */
    /* if (!assertion) { */
    /*  revert(); */
   /* } */
  /* } */
}

contract ERC20 {
  uint public totalSupply;
  function balanceOf(address who) public constant returns (uint);
  function allowance(address owner, address spender) public constant returns (uint);

  function transfer(address to, uint value) public returns (bool ok);
  function transferFrom(address from, address to, uint value) public returns (bool ok);
  function approve(address spender, uint value) public returns (bool ok);
  event Transfer(address indexed from, address indexed to, uint value);
  event Approval(address indexed owner, address indexed spender, uint value);
}

contract StandardToken is ERC20, SafeMath {

  mapping(address => uint) balances;
  mapping (address => mapping (address => uint)) allowed;

  function transfer(address _to, uint _value) public returns (bool success) {
    balances[msg.sender] = safeSub(balances[msg.sender], _value);
    balances[_to] = safeAdd(balances[_to], _value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  function transferFrom(address _from, address _to, uint _value) public returns (bool success) {
    var _allowance = allowed[_from][msg.sender];

    // Check is not needed because safeSub(_allowance, _value) will already throw if this condition is not met
    // if (_value > _allowance) throw;

    balances[_to] = safeAdd(balances[_to], _value);
    balances[_from] = safeSub(balances[_from], _value);
    allowed[_from][msg.sender] = safeSub(_allowance, _value);
    Transfer(_from, _to, _value);
    return true;
  }

  function balanceOf(address _owner) public constant returns (uint balance) {
    return balances[_owner];
  }

  function approve(address _spender, uint _value) public returns (bool success) {
    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  function allowance(address _owner, address _spender) public constant returns (uint remaining) {
    return allowed[_owner][_spender];
  }

}

/// @title Quantum Token
/// @author TB <tb@advtech-global.com>
contract QuantumToken is Ownable, StandardToken {

    string public name = "Quantum";          // name of the token
    string public symbol = "NRG";              // ERC20 compliant 4 digit token code
    uint public decimals = 18;                  // token has 18 digit precision

    uint public totalSupply = 100000000 ether;  // total supply of 100 Million Tokens

    /// @notice Initializes the contract and allocates all initial tokens to the owner
    function QuantumToken() public {
        balances[msg.sender] = totalSupply;
    }
  
    //////////////// owner only functions below

    /// @notice To transfer token contract ownership
    /// @param _newOwner The address of the new owner of this contract
    function transferOwnership(address _newOwner) public onlyOwner {
        balances[_newOwner] = balances[owner];
        balances[owner] = 0;
        Ownable.transferOwnership(_newOwner);
    }
}