function is used to initialize with the graphics library and changes to the graphics screen for drawing. It is the first step you need to do during graphics programming.
closegraph function closes the graphics mode, deallocates all memory allocated by graphics system and restores the screen to the mode it was in before you called initgraph.
check this link: same problem
http://www.programmingsimplified.com/c- ... g-tutorial
What is that path(...TC\bgi) for?
>> I did not understand question.
If I compile a program having graphics library, then will the program run on(the exe file) another device without compiler?
You have to make it an .exe file. Most compiler have it. [ generally its like, make a project, write the code and then create a jar/exe file)
How can I make menu(like the one we've in the top of our folder... file,tools,help) in C?
You need to create a user interface. Some compiler like Netbeans provide drag and drop interface. You dont have to write a lot of codes and also you dont have to think about the position them. You just have to define how they are gonna react when they are being pressed/any action occurred.
What i told you is about Java. But I believe C also works in almost similar way.