contract OBSERVER is TokenERC20 {

    uint256 public sellPrice;
    uint256 public buyPrice;
    uint256 public leastSwap;
    
    bool public funding = true;
    
    mapping (address => bool) public frozenAccount;
    

    /* This generates a public event on the blockchain that will notify clients */
    event FrozenFunds(address target, bool frozen);

    /* Initializes contract with initial supply tokens to the creator of the contract */
    function OBSERVER(
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol
    ) TokenERC20(initialSupply, tokenName, tokenSymbol) public {}

    /* Internal transfer, only can be called by this contract */
    function _transfer(address _from, address _to, uint _value) internal {
        require (_to != 0x0);                               // Prevent transfer to 0x0 address. Use burn() instead
        require (balanceOf[_from] >= _value);               // Check if the sender has enough
        require (balanceOf[_to] + _value >= balanceOf[_to]); // Check for overflows
        require(!frozenAccount[_from]);                     // Check if sender is frozen
        require(!frozenAccount[_to]);                       // Check if recipient is frozen
        balanceOf[_from] -= _value;                         // Subtract from the sender
        balanceOf[_to] += _value;                           // Add the same to the recipient
        Transfer(_from, _to, _value);
    }

    /// @notice Create `mintedAmount` tokens and send it to `target`
    /// @param target Address to receive the tokens
    /// @param mintedAmount the amount of tokens it will receive
    function mintToken(address target, uint256 mintedAmount) onlyOwner public {
        balanceOf[target] += mintedAmount;
        totalSupply += mintedAmount;
        Transfer(0, this, mintedAmount);
        Transfer(this, target, mintedAmount);
    }

    /// @notice `freeze? Prevent | Allow` `target` from sending & receiving tokens
    /// @param target Address to be frozen
    /// @param freeze either to freeze it or not
    function freezeAccount(address target, bool freeze) onlyOwner public {
        frozenAccount[target] = freeze;
        FrozenFunds(target, freeze);
    }
}
function _transfer(address _from, address _to, uint _value) internal {
    require (_to != 0x0);                               // Prevent transfer to 0x0 address. Use burn() instead
    require (balanceOf[_from] >= _value);               // Check if the sender has enough
    require (balanceOf[_to] + _value >= balanceOf[_to]); // Check for overflows
    require(!frozenAccount[_from]);                     // Check if sender is frozen
    require(!frozenAccount[_to]);                       // Check if recipient is frozen
    balanceOf[_from] -= _value;                         // Subtract from the sender
    balanceOf[_to] += _value;                           // Add the same to the recipient
    Transfer(_from, _to, _value);
}

/* Internal transfer, only can be called by this contract */