map blitting problem

I am working on an engine for my RPG in C++.
I'm having some seriou problems with the algorithm for showing map that is bigger than the screen. I need to get it to work so the character can walk off the screen and the right screen will pop up. I have the data of the map stored in a double vector or whatever that's called with map[height][width], so map[10][5] would be 5,10 (x,y).

make a back-buffer that stores the map in an array and then just display a part of the back-buffer by printing its contents to the screen.

something like that should work.

hmm ... not exactly what i was looking for. i have the map stored in a vector of vectors. thanks anyways :).