pragma solidity >=0.4.22 <0.6.0;
contract owned {
    address public owner;
    constructor() public {
        owner = msg.sender;
    }
    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }
    function transferOwnership(address newOwner) onlyOwner public {
        owner = newOwner;
    }
}
interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _extraData) external; }
contract TokenERC20 {
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    uint256 public totalSupply;
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    event Burn(address indexed from, uint256 value);
    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol
    ) public {
        totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
        balanceOf[msg.sender] = totalSupply;                    // Give the creator all initial tokens
        name = tokenName;                                       // Set the name for display purposes
        symbol = tokenSymbol;                                   // Set the symbol for display purposes
    }
    function _transfer(address _from, address _to, uint _value) internal {
        require(_to != address(0x0));
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value > balanceOf[_to]);
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }
    function transfer(address _to, uint256 _value) public returns (bool success) {
        _transfer(msg.sender, _to, _value);
        return true;
    }
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= allowance[_from][msg.sender]);     // Check allowance
        allowance[_from][msg.sender] -= _value;
        _transfer(_from, _to, _value);
        return true;
    }
    function approve(address _spender, uint256 _value) public
        returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }
    function approveAndCall(address _spender, uint256 _value, bytes memory _extraData)
        public
        returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);
        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, address(this), _extraData);
            return true;
        }
    }
    function burn(uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);  
        balanceOf[msg.sender] -= _value;            
        totalSupply -= _value;                     
        emit Burn(msg.sender, _value);
        return true;
    }
    function burnFrom(address _from, uint256 _value) public returns (bool success) {
        require(balanceOf[_from] >= _value);             
        require(_value <= allowance[_from][msg.sender]);    
        balanceOf[_from] -= _value;                         
        allowance[_from][msg.sender] -= _value;           
        totalSupply -= _value;                             
        emit Burn(_from, _value);
        return true;
    }
}contract DCCBToken is owned, TokenERC20 {
    uint256 public sellPrice;
    uint256 public buyPrice;
    mapping (address => bool) public frozenAccount;
    event FrozenFunds(address target, bool frozen);
    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol
    ) TokenERC20(initialSupply, tokenName, tokenSymbol) public {}
    function _transfer(address _from, address _to, uint _value) internal {
        require (_to != address(0x0));                         
        require (balanceOf[_from] >= _value);                  
        require (balanceOf[_to] + _value >= balanceOf[_to]);    
        require(!frozenAccount[_from]);                        
        require(!frozenAccount[_to]);                         
        balanceOf[_from] -= _value;                          
        balanceOf[_to] += _value;                              
        emit Transfer(_from, _to, _value);
    }function freezeAccount(address target, bool freeze) onlyOwner public {
        frozenAccount[target] = freeze;
        emit FrozenFunds(target, freeze);
    }function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner public {
        sellPrice = newSellPrice;
        buyPrice = newBuyPrice;
    } function buy() payable public {
        uint amount = msg.value / buyPrice;                 
        _transfer(address(this), msg.sender, amount); 
    } function sell(uint256 amount) public {
        address myAddress = address(this);
        require(myAddress.balance >= amount * sellPrice);  
        _transfer(msg.sender, address(this), amount);     
        msg.sender.transfer(amount * sellPrice);          
    }
}