I wrote this program in Qt Creator but I'm not sure how to run it. Here is my code:
#include <QtCore/QCoreApplication>
using namespace std;
#include <iostream>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
string str;
cin >> str;
cout << " str is : " << str;
return a.exec();
}
When I run it my console shows this:
Starting /home/hamed/qt programs/test3-build-desktop/test3...
...and nothing happens. What should I do?
When copy pasting your code, it runs for me as expected (well, it doesn't terminate, but runs). Here is what I did in command line:
cd testproject
qmake -project
qmake
make
./testproject
As mentioned in the comment above, Qt itself is a library, so you are probably referring to some IDE when saying running it from "within Qt" - behaviour there is solely dependent on what IDE you are using.
Update:
From your message
Starting /home/hamed/qt programs/test3-build-desktop/test3...
I assume that you are using the QtCreator IDE, which does not allow you to enter things to console when running. I don't know whether you can get it to do so, but it works if you enter your project directory in console and use ./projectname. The building part mentioned above will be handled by QtCreator.
Another update:
Check out this thread for information on how to get it to work directly from QtCreator.
nothing happens!!
Your program is expecting an input, as you written here:
cin >> str;
what should i do?
Just type in something and press enter.
Add QTimer::singleShot(0, &a, SLOT(quit())); before the line return a.exec(); and don't forget to #include <QtCore/QTimer> (or you can make life easier and import the everything #include <QtCore>).
The a.exec() enters an event loop which waits for an event; normally in the form of user input with a graphical user interface. This however is a command line program and there isn't really a way for a user to send an event so it sits and waits forever. This is useful for server type applications but not what you're doing here. :)
(Note, this is one of many reasons your application might appear to be doing nothing. You may need to follow several of these answers before your program does what you expect)