The <graphics.h> header is an old Borland BGI graphics library for doing direct graphics manipulation of your video hardware. Windows NT and later (4.0.something odd plus) won't let you do that.
If you mean "who has the header file - that I can use with DEV C++?"
then the answer is in the link I gave you. Download and follow their instructions on how to install it.
Otherwise you will have to ask again in a different way so that I can understand you better.