Thread: [qt and C++] Copied some example code but getting an error ~~~ Please help

First of all , I am new in qt and coming from Java
I want to run and compile some qt code so I can learn it , then I went to this website and saw they provided some qt examples
Qt 4.6: Analog Clock Example [trinitydesktop.org]
I use the latest version of the qt and I copied the code but I get some error please help !
http://s11.postimg.org/7w4rsg3v7/Scrshot1.png
http://s11.postimg.org/p854dvxcj/Scrshot2.png
http://s11.postimg.org/9ubfqfwcz/Scrshot3.png
http://s11.postimg.org/vs7wk8bdf/Scrshot4.png
http://s11.postimg.org/e4q3m11g3/Scrshot5.png
or
https://www.dropbox.com/sh/i2kze8hgbyp0s6t/RphTWF19NW
Errors:

Code:

mainwindow.obj:-1: error: LNK2005: main already defined in main.obj
debug\uwm.exe:-1: error: LNK1169: one or more multiply defined symbols found

then

I went to the directory of project and deleted mainwindow.cpp and mainwindow.h
and now errors are gone
But after I build it it didn't run the program
Please help !!!




http://s22.postimg.org/iqosatggx/Scrshot6.png
http://s22.postimg.org/d3sfdcdy9/Scrshot7.png
http://s22.postimg.org/m2ihqdiu9/Scrshot8.png
http://s22.postimg.org/4iz3m63s1/Scrshot9.png


and I get this error


http://s21.postimg.org/6z7t2mnx3/Scrshot11.png

Code:

11:58:21: Running steps for project uwm...
11:58:21: Configuration unchanged, skipping qmake step.
11:58:21: Starting: "C:\Qt\Qt5.0.2\Tools\QtCreator\bin\jom.exe" 
 C:\Qt\Qt5.0.2\Tools\QtCreator\bin\jom.exe -f Makefile.Debug
Error: dependent '..\uwm\mainwindow.cpp' does not exist.
jom: D:\qt\build-uwm-Desktop_Qt_5_0_2_MSVC2012_64bit-Debug\Makefile [debug] Error 2
11:58:21: The process "C:\Qt\Qt5.0.2\Tools\QtCreator\bin\jom.exe" exited with code 2.
Error while building/deploying project uwm (kit: Desktop Qt 5.0.2 MSVC2012 64bit)
When executing step 'Make'
11:58:21: Elapsed time: 00:00.

Solved thanks !!!