pragma solidity ^0.4.21;

contract ERC20Template {
    
    uint256 public totalSupply;

    function balanceOf(address _owner) public view returns (uint256 balance);

    function transfer(address _to, uint256 _value) public returns (bool success);

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success);

    function approve(address _spender, uint256 _value) public returns (bool success);

    function allowance(address _owner, address _spender) public view returns (uint256 remaining);

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}

contract ERC20 is ERC20Template {

    uint256 constant private MAX_UINT256 = 2**256 - 1;
    mapping (address => uint256) public balances;
    mapping (address => mapping (address => uint256)) public allowed;
    
    
    string public name;                   
    uint8 public decimals;                
    string public symbol;                 

    function ERC20(uint256 _initialAmount, string _tokenName, uint8 _decimalUnits, string _tokenSymbol) public {
        balances[msg.sender] = _initialAmount;               
        totalSupply = _initialAmount;                        
        name = _tokenName;                                   
        decimals = _decimalUnits;                            
        symbol = _tokenSymbol;                               
    }

    function transfer(address _to, uint256 _value) public returns (bool success) {
        require(balances[msg.sender] >= _value);
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        emit 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;
        }
        emit 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;
        emit Approval(msg.sender, _spender, _value); 
        return true;
    }

    function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }
}
contract UbiatarPlay is ERC20 {
    
    /* ERC20 */
    string public name = 'UbiatarPlay';
    string public symbol = 'UAC';
    uint8 public decimals = 8;
    
    /* UACToken */
    address owner; 
    address public crowdsale;
    string public version = 'v0.8';
    uint256 public totalSupply = 1000000000 * 10**uint(decimals);

    modifier onlyBy(address _account) {
        require(msg.sender == _account);
        _;
    }
    
    constructor() ERC20 (totalSupply, name, decimals, symbol) public {
        owner = msg.sender;
        crowdsale = address(0);
    }

    event Burn(address indexed burner, uint256 value);

    function burn(uint256 _value) public returns (bool success) {
        require(_value > 0);
        require(balances[msg.sender] >= _value);
        balances[msg.sender] -= _value;
        totalSupply -= _value;
        emit Transfer(msg.sender, address(0), _value);
        emit Burn(msg.sender, _value);
        return true;
    }

}