I have good knowledge of c++. But i have never done designing and coding for c++. That's why I want to do some dumy projects in c++. Is there any book available for such projects? or what will be good to overcome this problem?
Why write a "dummy" project? Write some real code! Write some code in the area of your interest viz graphics. A language is just the beginning - then comes OO design and libraries. If you can, join a company or part time work in your area of interest - this is the best way to test yourself.
If you face any problem, refer to the online book by Bruce Eckel "Thinking in C++" - it also has a print version. Or refer to Stroustrup's book "The C++ Programming Language".