$1-$ What is the output of the following main program? Justify your answer in each statement.int main $($XSmall$*$ ptrSmall;Small objSmall$(2,3)$;notSmall objBig$(3,5,9)$;ptrSmall $=$ &objSmall;cout $$ ptrSmall $->$add endl;ptrSmall $->$print$()$;ptrSmall $=$ &objBig;cout $$ ptrSmall $->$add endl;ptrSmall $->$print$()$;$\}//$end main$2-$ Rewrite in C$++$ the definition of the class that the member functions print, add, and destructor are virtual functions. Use the same drive program and repeat the question of Question $1\mathrm{.}3-$ Define an abstract class with all member functions pure virtual.