I want my c/c++ program's console window to chose a specific position. is it possible either within the program or by system call?
There are X server extensions that allow a program to specify where a window it creates should be drawn. I don't remember these off the top of my head, but given that it's part of the X libraries (which are presumably used directly or indirectly if the program is creating windows) they should be easy enough to find?
If, on the other hand, this is a console application looking to change the position and/or size of the virtual console from which it is launched... my understanding is that there is no system for doing so. It's possible to discover its dimensions and terminate with a message if it's too small, but actual direct control is not possible. This is because a console application could well be run in a dumb text console without the X (GUI) server running at all.
All that said: I think this question would possibly be more at home on Stack Overflow than on Ask Ubuntu?