Create a recursive function to print integer numbers vertically.

Question

Create a recursive function to print a multidigit number vertically. For example, 2378 should be printed

2
3
7
8

Test your program with numbers of different length.

Answer 1

You might find that 2378 % 10 == 8 is useful...

Answer 2

in haskell because thats probably not what your assignment is in and it will not be helpful

print_num = print . unlines . map show . vertnums
vertnums n =
    let (d,m) = divMod n 10
    in  case d of
        0 -> [m]
        x -> vertnums x ++ [m]

more code golf

toString c = [c]
print_num = print . unlines . map toString . show

this also works, i was surprised

print_num = print . unlines . map return . show

Answer 3

In quick-and-dirty python:

def recursive(x):
    if x > 10:
        print recursive(x/10)
    return x%10

Answer 4

Ruby, 5 lines ... Oh wait, this isn't code-golf

#!/usr/bin/ruby
def rp n
  rp n / 10 if n >= 10
  puts n % 10
end
rp ARGV[0].to_i

Clojure, your instructor will love it, trust me

 (defn rp [n]
   (if (>= n 10)
     (rp (quot n 10)))
   (println (rem n 10)))

nroff, a job-interview must-have, oh wait...

.pl 1
.de f
. if \\$1>=10 \{\
.   nr t \\$1/10
.   f \\nt
. \}
. nr t \\$1%10
\\nt
. br
..
.f 2378

Answer 5

PostScript

    /print_vertically {

        % Init all stuff
        /Palatino-Roman 12 selectfont % Long live Hermann Zapf!
        24 720 moveto % Sounds like a safe place to begin printing, for A4 or letter
        0 14.4 rmoveto % little trick to start 1 line higher than we will print

        doprint_vertically % call the main routine

        showpage % We're done!

       } def

    % The main routine
    /doprint_vertically {
        currentpoint exch pop 14.4 sub 24 exch moveto % move down one line
        dup 10 mod 1 string cvs show % compute remainder mod 10 and print 10
        10 idiv dup 0 ne % compute quotient
        { doprint_vertically } % if quotient != 0, recurse
        { pop } % else, clean up the stack
        ifelse % Never got to devise a satisfactory coding style for PostScript...
    } def

SO's pretty printer is really bad at displaying PostScript code... not really surprising ;-)

Answer 6

Brainfuck:

[>,----------][<][>[++++++++++.[-]++++++++++.----------]]

That's about as recursive as I can get it.