Should i use structure or classes in big and complex programs.

Question

I am a bit confused about which one to use so please tell me

Answer 1

Classes Generally used for large amounts of data.
To get more information check that:
http://www.differencebetween.info/difference-between-class-and-structure-in-cplusplus

Answer 2

Both of them should be used with any program size to represent data if it's less complicated than using the integrated types with in-place control code.