How to add a new function to a pre widget class to access in my application with out creating it as seperate class.

[Lavanya]

I am writing a serial port qt application in which only one header file one cpp file and one main cpp file is there .
Everything working fine when i opened serial port of write/read this i confirmed with qdebug messages i wrote to print. But nothing is printing on my terminal side in system but i can see data in text box. later i come to know local echo is not set through the qt application where to do so i saw reference example where they created seperate class and define echo set function and used in main class.
1.is that only method to print sent data in console along with text box in ui
2.if any other way can some one please guide me how to create a proper connection between opened terminal in system to textbox widget in my application.

[jsulm]

@Lavanya Can you please explain better? What echo function do you mean? What example do you mean?