How to design coffee vending machine in java

What are advantages and disadvantages of various approaches to generalisation in program design?

(without using the built in functions of C++)

Can the function by which we get values for object strictly follow the data hiding rule in oops?if no,why?e.g void student ::getdata() { coutname; - - - - }void main(){ student s; s.getdata(); getch();}

If we want that any wildcard characters in the command line arguments should be appropriately expanded, are we required to make any special provision? If yes, which?

Can there be at least some solution to determine the number of arguments passed to a variable argument list function?