Using cin in QtCreator

If you're doing "console"-style apps with no GUI, Qt Creator may not be the most appropriate IDE -- why not try Apple's own XCode, which probably comes on your OS DVD (as a separate installer), and worst-case can be freely downloaded by registering at Apple Developer Connection?

Edit: as the OP indicates that all they need is the location to Mac's terminal app, that's easy: it's /Applications/Utilities/Terminal.app.

In Preferences, under the Environment section, set the "Terminal" option to /Applications/Utilities/Terminal.app, as pointed out by Alex Martelli.

Then, in the Projects tab, under Run Settings, check the box marked "Run in Terminal".

Now, QtCreator will use Apple's built-in Terminal.app instead of Qt's console, allowing for interactive input.