pragma solidity ^0.4.24;



/**

 * @title ERC20Basic

 * @dev Simpler version of ERC20 interface

 * See https://github.com/ethereum/EIPs/issues/179

 */

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);

}



/**

 * @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) {

    // Gas optimization: this is cheaper than asserting 'a' not being zero, but the

    // benefit is lost if 'b' is also tested.

    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522

    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;

  }

}



/**

 * @title Basic token

 * @dev Basic version of StandardToken, with no allowances.

 */

contract BasicToken is ERC20Basic {

  using SafeMath for uint256;



  mapping(address => uint256) balances;



  uint256 totalSupply_;



  /**

  * @dev Total number of tokens in existence

  */

  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(0));

    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) {

    return balances[_owner];

  }

}



/**

 * @title ERC20 interface

 * @dev see https://github.com/ethereum/EIPs/issues/20

 */

contract ERC20 is ERC20Basic {

  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);

  event Approval(

    address indexed owner,

    address indexed spender,

    uint256 value

  );

}



/**

 * @title Standard ERC20 token

 *

 * @dev Implementation of the basic standard token.

 * https://github.com/ethereum/EIPs/issues/20

 * Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol

 */

contract StandardToken is ERC20, BasicToken {



  mapping (address => mapping (address => uint256)) internal allowed;



  /**

   * @dev Transfer tokens from one address to another

   * @param _from address The address which you want to send tokens from

   * @param _to address The address which you want to transfer to

   * @param _value uint256 the amount of tokens to be transferred

   */

  function transferFrom(

    address _from,

    address _to,

    uint256 _value

  )

    public

    returns (bool)

  {

    require(_to != address(0));

    require(_value <= balances[_from]);

    require(_value <= allowed[_from][msg.sender]);



    balances[_from] = balances[_from].sub(_value);

    balances[_to] = balances[_to].add(_value);

    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);

    emit Transfer(_from, _to, _value);

    return true;

  }



  /**

   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.

   * Beware that changing an allowance with this method brings the risk that someone may use both the old

   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this

   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:

   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729

   * @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) {

    allowed[msg.sender][_spender] = _value;

    emit Approval(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 specifying the amount of tokens still available for the spender.

   */

  function allowance(

    address _owner,

    address _spender

   )

    public

    view

    returns (uint256)

  {

    return allowed[_owner][_spender];

  }



  /**

   * @dev Increase the amount of tokens that an owner allowed to a spender.

   * approve should be called when allowed[_spender] == 0. To increment

   * allowed value is better to use this function to avoid 2 calls (and wait until

   * the first transaction is mined)

   * From MonolithDAO Token.sol

   * @param _spender The address which will spend the funds.

   * @param _addedValue The amount of tokens to increase the allowance by.

   */

  function increaseApproval(

    address _spender,

    uint256 _addedValue

  )

    public

    returns (bool)

  {

    allowed[msg.sender][_spender] = (

      allowed[msg.sender][_spender].add(_addedValue));

    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);

    return true;

  }



  /**

   * @dev Decrease the amount of tokens that an owner allowed to a spender.

   * approve should be called when allowed[_spender] == 0. To decrement

   * allowed value is better to use this function to avoid 2 calls (and wait until

   * the first transaction is mined)

   * From MonolithDAO Token.sol

   * @param _spender The address which will spend the funds.

   * @param _subtractedValue The amount of tokens to decrease the allowance by.

   */

  function decreaseApproval(

    address _spender,

    uint256 _subtractedValue

  )

    public

    returns (bool)

  {

    uint256 oldValue = allowed[msg.sender][_spender];

    if (_subtractedValue > oldValue) {

      allowed[msg.sender][_spender] = 0;

    } else {

      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);

    }

    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);

    return true;

  }



}



contract EKToken is StandardToken {

    string public name = "EKToken"; 

    string public symbol = "EK";

    uint public decimals = 8;

    uint public totalSupply = 5000000000 * (10 ** decimals);

    

    constructor() public {

        balances[msg.sender] = totalSupply;

    }

}