can't write C++ code on *.cu

is that true in *.cu we can’t include any
other language library except c library ?

bacause in my case , when i trying to include c++
library in the *.cu source code
it will occurs error

You can not link a library. Each function gets inlined in CUDA, so you need the source-code to be able to compile.

Also not all C++ things work in kernel-code (yet). Templates do work (and are supported in 2.1), a lot of other things not yet, and if they work now they might not work in 2.2. Note however that full C++ support is on the roadmaps that have been shown.