     //Dictionary to store variables
     fileprivate var variableDict = [String:Double]()
     
-    
     //UI Label display value
     fileprivate var displayValue: Double? {
         get{

    //(-> M) Set the variable in the dict with display value, and 
    //evaluate current set of operations with M with it.
    @IBAction func setVariableInDictionary(_ sender: UIButton) {
    }
    
    //(M) Add the variable to the set of brain operations
    @IBAction func useVariableInOperations(_ sender: UIButton) {
    }
    
    //User has touched an operation button

                formatter.numberStyle = .decimal
                formatter.maximumFractionDigits = Constants.NumDecimalDigits
                display.text = formatter.string(from: NSNumber(value: doubleValue))
            }else{
                display.text = "0"
                history.text = " "
