Error due to #include<graphics.h>

graphics.h is a non-standard header. Most likely it refers to the old BGI graphics library of the Turbo C DOS compiler. It will only work on that particular compiler. And of course DOS is a completely obsolete OS nowadays.

If you are interested in 3D graphics programming, then OpenGL and/or DirectX are indeed better, modern alternatives, supported by many compilers.

If you try to compile the source code with including “graphics.h” in code::blocks IDE you have to setup winBGIm library.

• Download WinBGIm from http://winbgim.codecutter.org/ or use (direct link)
• Extract it.
• Open graphics.h, go to line 302 change int right=0 to int top=0
• Copy graphics.h and winbgim.h files in include folder of your compiler directory.
• Copy libbgi.a to lib folder of your compiler directory
• In code::blocks open Settings >> Compiler and debugger >> linker settings
• Click Add button in link libraries part, browse and select libbgi.a file
• In right part (ie. other linker options) paste commands
  -lbgi -lgdi32 -lcomdlg32 -luuid -loleaut32 -lole32
• Click Ok
  
  

You can also check this video tutorial.