Write a program to convert any number in the decimal system (base 10) to a number in the binary system (base 2)
or vice verse.  
(Hint: in main function, you give a menu to let user select either converting from base 10 to base 2 or base 2 to base 10.)

Note:  
I.  Use stack concepts to write a function to convert any number in the decimal system (base 10) to a number in the binary system (base 2)

II. Do the method of converting a number in the binary system to a number in the decimal system in recursive way.
            Your function header is followed:
                  int Bin2Dec(string bin);