code a routine that picks (fairly) a random code, C, in the range 0 .. 1eD -1, and then scrolls the display (sequentially or randomly), until the first digit (left most) matches the first digit of C.

Does this mean that the implementation must actually choose C before displaying it digit by digit? Or would it (theoretically) be okay if the digits were chosen as they are being displayed (i.e. the second digit is not known to the program before the first has been shown)?