Suggest some functions which are continuous everywhere but differentiable no where??

well...i don't think there can be a function which will be non-differentiable everywhere.  you need to specify the domain. 

i agree with you norton

See http://www.goiit.com/posts/list/differenciation-wonders-never-cease-48342.htm

hey suryamahe i have 1 query regarding ur sol

ok /x/ is continuous everywhere but it is non differentiable only at criticle point here it is 0