How to format text output in c

Question

How do i change the font size etc. In c99

Answer 1

C has no concept of font size. It will just output characters. If you want to control the look of those characters, that's outside the purview of the standard.

As an example, Windows provides DirectX functions that you can specify font types and sizes for. As does Windows GDI. I have no doubt that any GUI will give you that sort of control as well (Gnome, KDE et al) but it has nothing to do with ISO C other than the fact you'll be able to call them from your C code.