Why there is no header file graphic.h in solo learn

Answer 1

graphics.h header had been removed from the Cpp a way back before.
and it's not that only sololearn don't have it,
all latest compilers don't have it.

OpenGl and OpenCv are open source third-party libraries to manage graphics and computer vision respectively.

Answer 2

It's not standard. C++ has no graphics component on it's own.

Answer 3

but in turboo c++ it has graphics.h as header file

Answer 4

It's noncompilant.
BTW, why are you using a decades old compiler?