@Andy314 said:

I dont know the files, thats the main requirement of my project, there fore I must use QtFtp.

I do not think that this is absolutely true. Probably your thinking is FTP based, which makes it harder to get the basic idea of QNetworkAccessManager. The downloading mechanism looked strange to me in the beginning as well. Therefore, I had integrated the supplied QFtp module into Qt 5. FTP is basically technology of the 1980's. Command-driven stepping from folder to folder. Listing in between until you have navigated to the place where you had to go. This is emulated within the QFtp for Qt5.
Anyway the actual need of QFtp is more a philosophic discussion in my opinion.
@Andy314 said:

I was able to compile it after the correction of a include error. What shall I do with the lot of output files now. Must I integrate this in my Qt current installation ?

@koahnig said:

@Andy314

QFtp is decrepated, but for compatibility Qt4 based applications you can add QtFtp

As already given in the first post follow the link and see the few steps.

The example is based on QNetworkAccessManager. However, you may use it directly or see how to create your required functionality based on QNetworkAccessManager

Your output should be basically 2 libs and 2 dlls (one for release and debug each). You can add them to your installation if you like.

@jelicicm
the exec() is typically called with a return at last position in main. Exec starts the event loop and continues until you quit the whole application.

I recommend that you check out the example delivered with QtFtp
This provides you a better start.

When using Qt it is recommended to have a sound basis of C++. Your code looks as you are more familiar with C. It may help your understanding to go through some C++ tutorial, if you are not familiar with OOP and C++.