I want to be able to put a letter at a random pixel on the screen, but not in one of the "text squares" that c++ uses with cout

I was told that graphics mode could do this, but I haven't found a function to place a letter at x/y pixel coordinates and not in the 80x25 grid of places for letters

for instance, instead of placing the letter A at (5,5) on the letter grid, i want to put it at pixel (5,5)

What can I use to do this in c++?