private void btnDepositActionPerformed(java.awt.event.ActionEvent evt) {                                         
      String userInput = txtDeposit.getText();
      int userInputInt;
      String userInputBinary="";
      userInputInt = Math.abs(Integer.parseInt(userInput));
       userInputBinary = Long.toBinaryString(userInputInt);
     
      this.set(userInputBinary);
      //if negative
      if (userInput.charAt(0) == '-') this.setSignBit("1");
     
    }