# continuous function and not differentiable [duplicate]

Possible Duplicate:
Function example? Continuous everywhere, differentiable nowhere

Is there any function that continuous in all places and not differentiable in all places?

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## marked as duplicate by Hagen von Eitzen, Micah, Martin Argerami, Henry T. Horton, Hans LundmarkDec 1 '12 at 19:12

Nice additional information: A randomly chosen continuous function is nearly "always" not differentiable in all places. For example the continous functions on $\left[0,1\right]$ that are not differentiable in all places are dense in all continous function on $\left[0,1\right]$ – user127.0.0.1 Dec 1 '12 at 18:15