How to create a web crawler?
The application search on google, handle all listed sites and access one by one and get something.
You might want to start with "QNetworkAccessManager":http://qt-project.org/doc/qt-4.8/QNetworkAccessManager.html
QString searchWord = "Hello";
QString request = "http://www.google.com.ua/#hl=en&output=search&q=" + searchWord;
After this you have to parse the result. That's the most difficult.
I've done some research on this in January.
First, QNetworkAccessManager is no solution, as it seems, as its a good HTTP source.
QtWebKit offers a lot of good stuff which you can use to crawl, f.e. it can extract all <a> tags (aka links).
But, the problem here is, QtWebKit is not threadsafe, so you'd have to handle multiple Processes doing the work, in order to speed up the process.