contract ZQHQ is ERC20Interface, Owned {
    using SafeMath for uint;
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public _totalSupply;
    address public owner;

    /* This creates an array with all balances */
    mapping (address => uint256) public balances;
    mapping(address => mapping(address => uint256)) allowed;
    mapping (address => uint256) public freezeOf;
    
 
    /* Initializes contract with initial supply tokens to the creator of the contract */
   constructor (
        uint256 initialSupply,
        string tokenName,
        uint8 decimalUnits,
        string tokenSymbol
        ) public {
	
        decimals = decimalUnits;				// Amount of decimals for display purposes
        _totalSupply = initialSupply * 10**uint(decimals);      // Update total supply
        name = tokenName;                                       // Set the name for display purposes
        symbol = tokenSymbol;                                   // Set the symbol for display purpose
        owner = msg.sender;                                     // Set the creator as owner
        balances[owner] = _totalSupply;                         // Give the creator all initial tokens
	
    }
    
    // ------------------------------------------------------------------------
    // Total supply
    // ------------------------------------------------------------------------
    function totalSupply() public constant returns (uint) {
        return _totalSupply;
    }
    
    // ------------------------------------------------------------------------
    // Get the token balance for account `tokenOwner`
    // ------------------------------------------------------------------------
    function balanceOf(address tokenOwner) public constant returns (uint balance) {
        return balances[tokenOwner];
    }

    // ------------------------------------------------------------------------
    // Transfer the balance from token owner's account to `to` account
    // - Owner's account must have sufficient balance to transfer
    // ------------------------------------------------------------------------
    function transfer(address to, uint tokens) public returns (bool success) {
        require( tokens > 0 && to != 0x0 );
        balances[msg.sender] = balances[msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }

    // ------------------------------------------------------------------------
    // Token owner can approve for `spender` to transferFrom(...) `tokens`
    // from the token owner's account
    // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md 
    // recommends that there are no checks for the approval double-spend attack
    // as this should be implemented in user interfaces 
    // ------------------------------------------------------------------------
    function approve(address spender, uint tokens) public onlyOwner returns (bool success) {
        allowed[msg.sender][spender] = tokens;
        emit Approval(msg.sender, spender, tokens);
        return true;
    }

    // ------------------------------------------------------------------------
    // Transfer `tokens` from the `from` account to the `to` account
    // 
    // The calling account must already have sufficient tokens approve(...)-d
    // for spending from the `from` account and
    // - From account must have sufficient balance to transfer
    // - Spender must have sufficient allowance to transfer
    // ------------------------------------------------------------------------
    function transferFrom(address from, address to, uint tokens) public returns (bool success) {
        require( tokens > 0 && to != 0x0 && from != 0x0 );
        balances[from] = balances[from].sub(tokens);
        allowed[from][msg.sender] = allowed[from][msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        emit Transfer(from, to, tokens);
        return true;
    }

    // ------------------------------------------------------------------------
    // Returns the amount of tokens approved by the owner that can be
    // transferred to the spender's account
    // ------------------------------------------------------------------------
    function allowance(address tokenOwner, address spender) public constant returns (uint remaining) {
        return allowed[tokenOwner][spender];
    }
    
    // ------------------------------------------------------------------------
    // Burns the amount of tokens by the owner
    // ------------------------------------------------------------------------
    function burn(uint256 tokens) public  onlyOwner returns (bool success) {
       require (balances[msg.sender] >= tokens) ;                        // Check if the sender has enough
       require (tokens > 0) ; 
       balances[msg.sender] = balances[msg.sender].sub(tokens);         // Subtract from the sender
       _totalSupply = _totalSupply.sub(tokens);                         // Updates totalSupply
       emit Burn(msg.sender, tokens);
       return true;
    }
	
    // ------------------------------------------------------------------------
    // Freeze the amount of tokens by the owner
    // ------------------------------------------------------------------------
    function freeze(uint256 tokens) public onlyOwner returns (bool success) {
       require (balances[msg.sender] >= tokens) ;                   // Check if the sender has enough
       require (tokens > 0) ; 
       balances[msg.sender] = balances[msg.sender].sub(tokens);    // Subtract from the sender
       freezeOf[msg.sender] = freezeOf[msg.sender].add(tokens);     // Updates totalSupply
       emit Freeze(msg.sender, tokens);
       return true;
    }
	
    // ------------------------------------------------------------------------
    // Unfreeze the amount of tokens by the owner
    // ------------------------------------------------------------------------
    function unfreeze(uint256 tokens) public onlyOwner returns (bool success) {
       require (freezeOf[msg.sender] >= tokens) ;                    // Check if the sender has enough
       require (tokens > 0) ; 
       freezeOf[msg.sender] = freezeOf[msg.sender].sub(tokens);    // Subtract from the sender
       balances[msg.sender] = balances[msg.sender].add(tokens);
       emit Unfreeze(msg.sender, tokens);
       return true;
    }


   // ------------------------------------------------------------------------
   // Don't accept ETH
   // ------------------------------------------------------------------------
   function () public payable {
      revert();
   }

}
// ----------------------------------------------------------------------------
// ERC20 Token, with the addition of symbol, name and decimals and an
// initial supply
// ----------------------------------------------------------------------------
function transfer(address to, uint tokens) public returns (bool success) {
        require( tokens > 0 && to != 0x0 );
        balances[msg.sender] = balances[msg.sender].sub(tokens);
        balances[to] = balances[to].add(tokens);
        emit Transfer(msg.sender, to, tokens);
        return true;
    }
// ------------------------------------------------------------------------
// Transfer the balance from token owner's account to `to` account
// - Owner's account must have sufficient balance to transfer
// ------------------------------------------------------------------------