Can I travel to spain with a swiss resident permit C?
I am planning of going to Spain, and would like to know if I could travel to spain with my swiss resident permit and my other passport (as I can travel to france with my swiss resident permit)? And the guys traveling with me has a shengen visa, is that okay?
Thanks!

Yes, the Swiss type C residence permit waives the visa requirement to the other Schengen countries; same applies to a visa issued by Switzerland if it is a type C visa and it states valid for "Schengen States" in the first column.
Source(s):
http://www.bfm.admin.ch/etc/medialib/data/migration/rechtsgrundlagen/weisungen_und_kreisschreiben/Weisungen_Visa.Par.0029.File.tmp/anh1-liste3b_visafrei-schengen-e.pdf ..