pragma solidity ^0.4.24;

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }

  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    // uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return a / b;
  }

  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}

contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint256;
    
  mapping (address => uint256) balances;

  uint256 totalSupply_;
  
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  /**
  * @dev transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0x0));
    require(_value <= balances[msg.sender]);

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of. 
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256 balance) {
    return balances[_owner];
  }
}

contract ERC20 is BasicToken {
  function allowance(address owner, address spender) public view returns (uint256);
  function transferFrom(address from, address to, uint256 value) public returns (bool);
  function approve(address spender, uint256 value) public returns (bool);
}

contract StandardToken is ERC20 {
  mapping (address => mapping (address => uint256)) allowed;

  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0x0));
    require(_value <= balances[msg.sender]);
    require(_value <= allowed[_from][msg.sender]);

    balances[_to] = balances[_to].add(_value);
    balances[_from] = balances[_from].sub(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);

    emit Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Aprove the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
   /** require((_value == 0) || (allowed[msg.sender][_spender] == 0)); **/
    allowed[msg.sender][_spender] = _value;
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifing the amount of tokens still avaible for the spender.
   */
  function allowance(address _owner, address _spender) public view returns (uint256) {
    return allowed[_owner][_spender];
  }
}

contract ETCVToken is StandardToken {
    string public name = "Ethereum Classic Vision";
    string public symbol = "ETCV";
    uint8 public decimals = 18;
      
    uint256 INITIAL_SUPPLY = 5000000000000000000000000;
    bool isNotInit = true;
    uint public price = 50;
    address owner = 0x84caFAFf8EFd3020209Ae93EA1F240487ad9332F;
    
    function initContract() external {
        require(isNotInit);
        totalSupply_ = INITIAL_SUPPLY;
        balances[address(owner)] = totalSupply_;
        emit Transfer(address(this), address(owner), INITIAL_SUPPLY);
        isNotInit = false;
    }
    
    function () payable external {
        require(msg.value > 0);
        uint tokens = msg.value.mul(price);
        balances[msg.sender] = balances[msg.sender].add(tokens);
        emit Transfer(address(this), msg.sender, tokens);
        address(owner).transfer(msg.value);
    }
}