Raspberry pi GPIO data send to APP

I have a simple task. Need to read data from a sensor over Raspberry Pi GPIO pin and send it to the Blynk APP.
But I am confused because much of info I see here is for arduino. Which librarys should I use and what is the simplest way to do my task ? I’m new to blink and willing to give it a try because it was said to be simple.
./blynk (test script) is working.

Hello. Please have a look here - http://docs.blynk.cc/#hardware-set-ups-raspberry-pi

Yes, I’ve done it, thanks. Unfourtunately it doesn’t help a lot.
there are some examples, but they are in javascript and don’t have comments.
Do you have examples in C ?

To put in my code I have to edit main.cpp is that right ?