I wonder why these codes stands for. What does that means?

[SHALANES]

What does (15U) mean ? Is that a specific useage declaring a number?

What does " =='\n' " means ?

After a long period of learning , I'm now trying to read and understand some projects , but there are still some question.
Hoping someone can answer me , thanks a lot .

[Karl Ylvisaker]

Hello,

What does (15U) mean ? Is that a specific useage declaring a number?

The suffix is there to specify the type of the defined constant.
Please see this stackoverflow answer for more detail.

What does " =='\n' " means ?

the character '\n' is the newline character.

After a long period of learning , I'm now trying to read and understand some projects , but there are still some question.
Hoping someone can answer me , thanks a lot .

No problem at all, we're happy to help! :)

Best regards,
Karl 

[SHALANES]

Thanks , that really helps , a lot .

Have a nice day .

[Karl Ylvisaker]

SHALANES said:

Thanks , that really helps , a lot .

Great, I am happy to hear that!

SHALANES said:

Have a nice day

Thanks, I hope you have a nice day as well! :)

Please do not hesitate to open another ticket if you have any other issues or questions.

Good luck with your development!

Best regards,
Karl