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)
        1. Keep dividing the number by 2 and replace the number by quotient until the number is zero.
        2. Push the remainder to a stack each time.
        3. Pop all elements from the stack to a vector.

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);

The following is a hint:
    M_bin('0') = 0
    M_bin('1') = 1
    M_bin(<bin_num>'0') = 2 * M_bin(<bin_num>)
    M_bin(<bin_num>'1') = 2 * M_bin(<bin_num>) + 1

example:

Mbin("10110")=2*Mbin("1011")
   =2*[2*Mbin("101")+1]
   =2*{2*[2*Mbin("10")+1]+1}
   =2*{2*[2*(2*Mbin('1'))+1]+1}
   =2*{2*[2*(2*1)+1]+1}
   =2*{2*[2*2+1]+1}
   =2*{2*5+1}
   =2*11
   =22