Clearscreen--I dont get it...

In console programs, do you ever notice that the screen flickers when you refresh the screen too much? For example, when i am making tetris, as the block falls down further and further, the console flashes every time it redraws the screen.

But then im wondering, how can First Person Shooters run at 80+ frames/second and not flash at all. Is the console clearscreen method flawed? I mean, in games like Counterstrike, it renders the screen much more often than in my console tetris yet it never flickers.

Someone tell me what is with this please.

Almost all games use double (or triple) buffering. If you don't know what that is, Google for it.

to be more specificamigated.
in 3d games you have a 3d acclartor. graphics card

when using directx d3d openGL etc. your program basicly talks to the card.

when using a console your program talks to the OS.
then waits for the os to take control.
then when the os finishes its "who the hell knows what" it flushes your input.
then retruns control back to your program. to sum it up

flashing occurs when you let the user see you drawing to the screen.

buffer flipping "double (or triple) buffering" is when you display the first buffer to the screen and you draw on the second. when your finished drawing you then flip/switch the buffers(or pointers to the buffers) so that the frame you just drew is now the one being displayed.

[edit]
a good idea is to make a char* buffer draw/write/dance to it then flush when your done.