private void BtnDivide_Click(object sender, RoutedEventArgs e)
        {
            string trigger = "BtnDivide";

            sb.Clear();

            if ((subInput.HasValue == true &&
                 mainInput.HasValue == true))
            {
                this.Execute(subInput.Value, mainInput.Value);
                BinaryOperations bin = new BinaryOperations();
                SubInput.Text = bin.OperatorReplacer(SubInput.Text, trigger);
            }
            else if (subInput == null)
            {
                subInput       = int.Parse(MainInput.Text);
                Operator.Text  = OperatorConstants.DivideSymbol.ToString(); //
                SubInput.Text += sb.Append(subInput).ToString() + Operator.Text;

                if (mainInput != null && subInput != null)
                {
                    this.Execute(subInput.Value, mainInput.Value);
                }
            }
            else if (subInput != null && mainInput == null)
            {
                mainInput      = int.Parse(MainInput.Text);
                SubInput.Text += sb.Append(mainInput).ToString() + Operator.Text;
                this.Execute(subInput.Value, mainInput.Value);

                Operator.Text = OperatorConstants.DivideSymbol.ToString();//
                sb.Clear();

                /* Replace operator symbol*/
                int subLen = SubInput.Text.Length - 1;

                if (SubInput.Text != String.Empty &&
                    SubInput.Text.Substring(subLen, 1) != OperatorConstants.DivideSymbol.ToString()) //
                {
                    BinaryOperations bin = new BinaryOperations();
                    SubInput.Text = bin.OperatorReplacer(SubInput.Text, trigger);
                }
            }
            else
            {
                MessageBox.Show("An Error occured", "Warning");
            }
            isClicked    = true;
            equalTrigger = false;
        }