Is there any way to convert a BIN file into a code?

Probably the best you can do is to disassemble the object code. Not that that's going to help you much as this will return Assembler codes, and not C language (or any other High Level Language). Depending on the optimization level, there may be very little resemblance between the assembler code and the original C code. That's because during optimization the compiler might eliminate unneeded variables, unroll loops, re-order code, and whole host of other things to make the code more efficient. If the object code has been also stripped of debug symbols, then there's very little to go on to help work out what an area (e.g. a struct) might be used for.

You better invest your time in some Learn C tutorial instead of try to cheat.
This "reverse engineering" isnt so easy because it may not work or the resulting code is bizarre. Functions may have names like "func1" and so on.
So you may end in a mess after a bunch of hours. In this time may have solved your task after learning some basics.