Re: difference between the gcc and windows c
See C is C, GCC is a compiler available for several OSs and platforms for C,C++,OBJ-C etc... . Even for Windows.
Turbo C OR VC are also compilers for C language available for DOS and Windows respectively.
Before knowing difference we should know the similarity. Both support ANSI C. AND extend it to support few extensions. Those extensions are "Compiler specific extensions" And found in the Documentations.
Next GCC generally generate ELF on UNIX variant system and can generate COFF too for DOS(DJGPP)
on the other hand Turbo C generates OMF format OBJ files and linker links it to the platform specific EXE file (MZ EXE or PE EXE)
VC generates OBJ and links to PE EXE only (AFAIK)
The last ( NOT Least) and most important difference is GCC is open source and according to need the Back-End for several architecture could be written. But Both TC and VC are Proprietary Hence no such feature to generate different Backend code.