Question

How do I write a hello world program in C......... in 3d!

Answer 1

The easiest way would probably be using GLUT and glutStrokeCharacter. If you want to go further, you could parse the outline of a font's characters (how you do this depends on the OS and/or frameworks you use; look at GetGlyphOutline in windows or FT_Outline_Decompose for Freetype) and build your own mesh (for example an extrusion of the glyph) for each character that you then render

Answer 2

It depends on how fancy you want to get. Rendering text and images on your own is surprisingly painful. You'll probably want to use SDL to get an OpenGL context, and good luck from there.