problem in installing Voro++

Hello Ahmed,
I cannot recommend compiling your own LAMMPS version under Windows. You should either download a precompiled executable. Look on the LAMMPS website, Axel (very active on this list) has done all the legwork to get a working windows executable. I do think it does include the VORONOI module. Otherwise compile and run it on a Linux/Unix machine.
Your problem is rather elementary though, the “%” is not part of what you are supposed to type in! I’m also not sure if cygwin has the ‘sudo’ command. But as I said, this is a bit of a moot point.