pragma solidity ^0.4.16;

contract XBYR{



    uint256 constant private MAX_UINT256 = 2**256 - 1;

    mapping (address => uint256) public balances;

    mapping (address => mapping (address => uint256)) public allowed;

    /*

    NOTE:

    The following variables are OPTIONAL vanities. One does not have to include them.

    They allow one to customise the token contract & in no way influences the core functionality.

    Some wallets/interfaces might not even bother to look at this information.

    */

    uint256 public totalSupply;

    string public name;                   //fancy name: eg Simon Bucks

    uint8 public decimals;                //How many decimals to show.

    string public symbol;                 //An identifier: eg SBX

     event Transfer(address indexed _from, address indexed _to, uint256 _value); 

    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

   

   

    function XBYR() public {

        balances[msg.sender] = 1000000000000;               // Give the creator all initial tokens

        totalSupply = 1000000000000;                        // Update total supply

        name = "YRCoin";                                   // Set the name for display purposes

        decimals =4;                            // Amount of decimals for display purposes

        symbol = "XBYR";                               // Set the symbol for display purposes

    }





    function transfer(address _to, uint256 _value) public returns (bool success) {

        require(balances[msg.sender] >= _value);

        balances[msg.sender] -= _value;

        balances[_to] += _value;

        Transfer(msg.sender, _to, _value);

        return true;

    }



    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {

        uint256 allowance = allowed[_from][msg.sender];

        require(balances[_from] >= _value && allowance >= _value);

        balances[_to] += _value;

        balances[_from] -= _value;

        if (allowance < MAX_UINT256) {

            allowed[_from][msg.sender] -= _value;

        }

        Transfer(_from, _to, _value);

        return true;

    }



    function balanceOf(address _owner) public view returns (uint256 balance) {

        return balances[_owner];

    }



    function approve(address _spender, uint256 _value) public returns (bool success) {

        allowed[msg.sender][_spender] = _value;

        Approval(msg.sender, _spender, _value);

        return true;

    }



    function allowance(address _owner, address _spender) public view returns (uint256 remaining) {

        return allowed[_owner][_spender];

    }   

}