Qt4 tutorial for absolute beginners
Author, (c): sector at ynet dot sk, please do not copy without permission.
If you have experience with programming in C/C++ (or at least have basic knowledge about principles of object oriented programming) and you want to learn Qt4, this tutorial is for you. This tutorial is especially dedicated to beginners. This tutorial is intended to be more practical than theoretical. It focuses on Qt4, no previous major versions of Qt are discussed here.
The reason why I decided to write this tutorial is that there is real lack of Qt tutorials for real beginners, people who want to start with Qt4 but they just don't know how. Qt documentation is really nice written, however it is hard to understand for average programmer. Examples bundled with Qt distribution are impressive but most of them are very difficult for beginner to learn from.
My first Qt GUI application tested with Qt 4.4.3.
Can an object fall through mass 5 times greater than itself nearly as fast as it would fall through air?
(When only force available is gravity?) More..
WTC Twin Towers collapse, did you know that:
Maximum temperature burning jet-fuel can reach in open-air conditions is about 1000°C. Structural steel melts at 1510°C. How is it possible that molten metal was pouring out of the WTC South Tower ? And pools of molten metal was found at the Ground Zero ? See more reports of molten metal at Ground Zero. See also NIST engineer John Gross responds to question about molten metal.
If you took upper-most floor of WTC and dropped it, it would fall through air and hit the ground in time about 10 seconds. Time of real WTC collapse was about 10 seconds! Watch video to confirm. Can debris fall through steel columns and concrete floors as fast as it would fall through air ?
Under zone of aircraft impact WTC Towers had 75/90 undamaged floors. How is it possible that this undamaged part of the building, which always had born weight of the upper floors with no problem, during the collapse provided virtually NO resistance to the section above ?
Look at this videos of WTC "collapse": video1, video2. Isn't what we see a building exploding to dust from top to bottom ?
On September 11th, 2001, third skyscraper, WTC 7 collapsed several hours after WTC Towers came down, allegedly due to fire and damage. Watch videos of this collapse:
There is no way fire/damage could cause this swift, systematic, straight-down collapse, and transform huge 47-floor steel structure into a small pile of rubble in matter of seconds. This building was brought down by professional controlled demolition. Official reports say that fire/damage caused this.
Watch technical analysis of WTC collapse by Richard Gage - architect with 20+ years experience with buildings design/construction
Online at Google Video: Architect Richard Gage - How Towers Fell
Direct download of hires 700MB avi: 911.Blueprint.for.Truth.2008.Edition.DVDRip.XviD (2008 Edition)
Table of contents:
I want to say a word of thanks to following people for helping me with this tutorial:
- azark - for correcting the grammar and typos
30.11.2008 - updated Preparations section to reflect latest changes, Qt4 on Windows can be installed via automated installer, no need to compile anymore
Your comments/feedback/bug/typo/inaccuracy reports or help with writing this tutorial are welcome.
Your feedback is very importat for me. I need to know if writing of this tutorial is worth the effort.
The database appears to be down.
painting with Qt - very simple example
clicking grid like widget