A question on QT 4 Slots

Okay, about a year or two ago when I wasn't as knowledgable about programming, I was tinkering with QT 4 to make a program that made binary decisions. Enter two strings in two separate QLineEdit child widgets, hit a button and the computer goes through 19 calls of rand() to find out which one to choose. All parts I found to work except the slots never fucking connected. Kept throwing a runtime error saying no slot existed. Today after looking back at my code and wanting to actually get into QT programming seriously, I still can't figure out why the fuck it isn't working.

Can anyone here who knows QT4 find out why the fuck the slot doesn't connect in this code?

mainwindow.hpp
http://pastebin.com/RSVjkzKV
mainwindow.cpp
http://pastebin.com/PRK1XvGt
And main.cpp was just this:
http://pastebin.com/nU12MMBs

>>4

Stop being a namefag and don't post if you can't answer a fucking question.