data_full/CVE_clean/2018-11239.sol

pragma solidity ^0.4.18;
contract Hexagon {
  string public constant name = "Hexagon";
  string public constant symbol = "HXG";
  uint8 public constant decimals = 4;
  uint8 public constant burnPerTransaction = 2;
  uint256 public constant initialSupply = 420000000000000;
  uint256 public currentSupply = initialSupply;
  mapping (address => uint256) public balanceOf;
  mapping (address => mapping (address => uint256)) public allowance;
  function Hexagon() public {
    balanceOf[msg.sender] = initialSupply;
  }
  function transfer(address _to, uint256 _value) public returns (bool success) {
    _transfer(msg.sender, _to, _value);
    return true;
  }
  function totalSupply() public constant returns (uint) {
    return currentSupply;
  }
  function burn(uint256 _value) public returns (bool success) {
    require(balanceOf[msg.sender] >= _value);
    balanceOf[msg.sender] -= _value;
    balanceOf[0x0] += _value;
    currentSupply -= _value;
    Burn(msg.sender, _value);
    return true;
  }
  function approve(address _spender, uint256 _value) public returns (bool success) {
    require(_value == 0 || allowance[msg.sender][_spender] == 0);
    allowance[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }
  function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
    require(allowance[_from][msg.sender] >= _value);
    allowance[_from][msg.sender] -= _value;
    _transfer(_from, _to, _value);
    return true;
  }
  function _transfer(address _from, address _to, uint _value) internal {
    require (_to != 0x0);
    require (balanceOf[_from] >= _value + burnPerTransaction);
    require (balanceOf[_to] + _value > balanceOf[_to]);
    balanceOf[_from] -= _value + burnPerTransaction;
    balanceOf[_to] += _value;
    balanceOf[0x0] += burnPerTransaction;
    currentSupply -= burnPerTransaction;
    Burn(_from, burnPerTransaction);
    Transfer(_from, _to, _value);
  }
  event Transfer(address indexed from, address indexed to, uint256 value);
  event Burn(address indexed from, uint256 value);
  event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}