IGNOU BCA CBS-031 previous years question papers you can download from here. Thanks to original up loader.C++ programming old question papers got some advantage. Question are repeating.
My suggestion is prepare all previous year questions then start preparing other concepts. For IGNOU BCA repetition is very less but for this subject it seems some exception.
For every concept try to learn one sample program. For example class concept, learn one sample example and without fail write example in exam. May get some extra marks.