send & recuve via socket

[tbscope]

I wrote it in main.cpp.

what is te meaning of moc at "main.moc"

It's the meta object compiler. It makes it possible to use Qt signals and slots, among other things.

is my way correct for connecting to the serve?

Your slot connection is not correct.
The slot is not part of the app.

You also need to create an object based on Qconnect.

Might I suggest your first learn c++?

[squidge]

tbscope speaks the truth: Please learn how to write a basic Qt application before trying to do socket programming - if you structure your program correctly and actually create an instance of the class that contains your slot, you would have a much better chance of your code doing what you want.

(This should really be in the newbie forum, too)