# Code Golf Christmas Edition: How to print out a Christmas tree of height N

Given a number N, how can I print out a Christmas tree of height N using the least number of code characters? N is assumed constrained to a minimum value of 3, and a maximum value of 30 (bounds and error checking are not necessary). N is given as the one and only command line argument to your program or script.

All languages appreciated, if you see a language already implemented and you can make it shorter, edit if possible - comment otherwise and hope someone cleans up the mess. Include newlines and White Spaces for clarity, but don't include them in the character count.

A Christmas tree is generated as such, with its "trunk" consisting of only a centered "*"

N = 3:

   *
***
*****
*


N = 4:

    *
***
*****
*******
*


N = 5:

     *
***
*****
*******
*********
*


N defines the height of the branches not including the one line trunk.

Merry Christmas PPCG!

# Brainfuck, 240 characters

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


Not yet done. It works, but only with single-digit numbers.

EDIT: Done! Works for interpreters using 0 as EOF. See NOTEs in commented source for those with -1.

EDIT again: I should note that because Brainfuck lacks a standard method for reading command line arguments, I used stdin (standard input) instead. ASCII, of course.

EDIT a third time: Oh dear, it seems I stripped . (output) characters when condensing the code. Fixed...

Here's the basic memory management of the main loop. I'm sure it can be heavily optimized to reduce the character count by 30 or so.

1. Temporary
2. Copy of counter
3. Counter (counts to 0)
4. Space character (decimal 32)
5. Asterisk character (decimal 42)
6. Number of asterisks on current line (1 + 2*counter)
7. Temporary
8. New line character
9. Temporary?
10. Total number of lines (i.e. input value; stored until the very end, when printing the trunk)

Condensed version:

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


And the pretty version:

ASCII to number
,>
++++++++[-<------>]  = 48 ('0')

Second digit (may be NULL)
,
NOTE:   Add plus sign here if your interpreter uses negative one for EOF
[ NOTE: Then add minus sign here
>++++++++[-<------>]
<<[->++++++++++<]>>  Add first digit by tens
]

Duplicate number
<[->+>+>>>>>>>+<<<<<<<<<]>>

Space char
>>++++++++[-<++++>]

Asterisk char
>++++++[-<+++++++>]

Star count
+

New line char
>>>++[-<+++++>]<<<

<<<

Main loop
[
-[>.<-]

Undo delete
<[-<+>>+<]
<[->+<]
>>

Print stars
>>>[-<.>>+<]

Add stars and print new line
>[-<+>]
>.<
<++

<<<

-<->
End main loop
]

Print the trunk
>>>>>>>
-[-<<<<<<.>>>>>>]
<<<<<.

Merry Christmas =)

• my brain feels f.....sick
– JoshBerke
Jan 22, 2009 at 0:14
• Oh my god. Jul 7, 2009 at 0:04
• I found this version online that's only 127 bytes when you delete unnecessary characters. Nov 14, 2019 at 0:15

# Perl, 50 chars

(1 relevant spaces)

perl: one line version:

print$"x($a-$_),'*'x($_*2+1),$/for 0..($a=pop)-1,0


and now with more whitesapce:

print $" x ($a - $_ ), #"# Syntax Highlight Hacking Comment '*' x ($_ * 2  + 1),
$/ for 0 .. ($a = pop ) - 1, 0;

$perl tree.pl 3 * *** ***** *$ perl tree.pl 11
*
***
*****
*******
*********
***********
*************
***************
*****************
*******************
*********************
*
$ ### Expanded Explanation for Non-Perl Users. # print$Default_List_Seperator ( a space )
#     repeated ( $a -$currentloopiterationvalue ) times,
print $" x ($a - $_ ), #"# print '*' repeated($currentloopiteration * 2 + 1 ) times.
'*' x ( $_ * 2 + 1), # print$Default_input_record_seperator ( a newline )
$/ # repeat the above code, in a loop, # iterating values 0 to ( n - 1) , and then doing 0 again for 0 .. ($a = pop ) - 1, 0;
# prior to loop iteration, set n to the first item popped off the default list,
#   which in this context is the parameters passed on the command line.

• Holy crap... perl truly is unreadable.
– zenazn
Dec 25, 2008 at 17:20
• @zenazn, also, it should be noticed that most golfing is BAD code in any language. If this were a competition for the cleanest code, we could win that too. Dec 25, 2008 at 17:23
• @zenazn: proof, you can see us collaborating and improving each others code above, this proves WE can read EACH OTHERS code perfectly fine. Dec 25, 2008 at 17:28
• PS: Thanks for the explanation for non-Perl programmers. It's still pretty unreadable, but at least it makes sense. I guess you get used to it after a while.
– zenazn
Dec 25, 2008 at 18:11
• @RobH: J is the child of APL. In some senses, it's more unreadable because it doesn't use APL's character set with a special symbol for every operation -- it overloads ASCII characters with multiple meanings, instead. stackoverflow.com/questions/392788/1088931#1088931 Jul 6, 2009 at 20:01

# J, 24 characters

(,{.)(}:@|."1,.])[\'*'$~  (,{.)(}:@|."1,.])[\'*'$~5
*
***
*****
*******
*********
*


Explanation:

'*'$~5 ***** [\'*'$~5
*
**
***
****
*****


Then }:@|."1 reverses each row and strips off the last column, and ,. staples it to ].

Then ,{. pastes the first column onto the bottom.

Previous entries:

29 characters, no spaces at all.

   ((\:i.@#),}.)"1$&'*'"0>:0,~i.3 * *** ***** * ((\:i.@#),}.)"1$&'*'"0>:0,~i.11
*
***
*****
*******
*********
***********
*************
***************
*****************
*******************
*********************
*


   NB. count from 1 to n, then 1 again
>:0,~i.3
1 2 3 1
NB. replicate '*' x times each
$&'*'"0>:0,~i.3 * ** *** * NB. reverse each row (\:i.@#)"1$&'*'"0>:0,~i.3
*
**
***
*
}."1$&'*'"0>:0,~i.3 * ** NB. paste together ((\:i.@#),}.)"1$&'*'"0>:0,~i.3
*
***
*****
*

• With just 9 more characters you can give this function a name: c=:[:((\:i.@#),}.)"1[:$&'*'"0[:>:0,~i. Jul 6, 2009 at 20:45 • What, do you guys use some sort of J documentation library to understandable-ize the code? :) – RCIX Nov 20, 2009 at 1:14 ### Language: Python (through shell), Char count: 64 (2 significant spaces) python -c " n=w=$1
s=1
while w:
print' '*w+'*'*s
s+=2
w-=1
print' '*n+'*'"

$sh ax6 11 * *** ***** ******* ********* *********** ************* *************** ***************** ******************* ********************* *  • what I like most about this solution is that python makes it really hard to write obscure code, it's one of the most readable solutions – Georg Schölly Dec 26, 2008 at 0:46 • You're using the shell to process the argument, which isn't in the spirit of code golf IMO. Using "import sys" and "n=w=int(sys.argv[1])" and an indent of 1 character for the loop body, I come up with 89 characters for this version. – Joshua Swink Dec 26, 2008 at 19:19 • This is how I did it before. The spirit of this question is to have fun, and in addition there was no specification of using only one language :) See the brainfuck answer, for example; no arguments. – tzot Dec 26, 2008 at 20:56 Language: Windows Batch Script (shocking!) @echo off echo Enable delayed environment variable expansion with CMD.EXE /V rem Branches for /l %%k in (1,1,%1) do ( set /a A=%1 - %%k set /a B=2 * %%k - 1 set AA= for /l %%i in (1,1,!A!) do set "AA=!AA! " set BB= for /l %%i in (1,1,!B!) do set BB=*!BB! echo !AA!!BB! ) rem Trunk set /a A=%1 - 1 set AA= for /l %%i in (1,1,!A!) do set "AA=!AA! " echo !AA!*  • masochist! I like it – Colin Pickard Jan 8, 2009 at 14:17 • Very nice... you get +1 – ojblass Apr 26, 2009 at 4:49 • Delayed variable expansion can be enabled using the setlocal enabledelayedexpansion command. Jul 30, 2009 at 17:49 • dude. seriously? – Earlz Dec 1, 2009 at 2:34 • Can't make it work. First time I try though. Nov 15, 2013 at 10:27 ### Ruby, 64 bytes n=ARGV[0].to_i ((1..n).to_a+[1]).each{|i|puts' '*(n-i)+'*'*(2*i-1)}  n=$*[0].to_i
((1..n).to_a<<1).each{|i|puts' '*(n-i)+'*'*(2*i-1)}


Merry Christmas all!

Edit: Improvements added as suggested by Joshua Swink

• This is a very nice line of Ruby.
– zenazn
Dec 25, 2008 at 17:17
• Did I seem too abrubt? Sorry, not my intention! Merry XMas! :)
– tzot
Dec 25, 2008 at 20:08
• Didn't mean to be mean either, and of course you were right! Merry Xmas!
– user4812
Dec 25, 2008 at 20:47
• I recently found the "Try Ruby" webpage, it looks like such a lovely programming language! :)
– Aistina
Dec 26, 2008 at 0:04
• On 1.9, you can save some more chars: n=$*[0].to_i;puts [*1..n,1].map{|i|" "*(n-i)+"*"*(2*i-1)} brings it down to 58. – manveru Sep 14, 2010 at 10:05 ### Language: C#, Char count: 120 static void Main(string[] a) { int h = int.Parse(a[0]); for (int n = 1; n < h + 2; n++) Console.WriteLine(n <= h ? new String('*', n * 2 - 1).PadLeft(h + n) : "*".PadLeft(h + 1)); } }  Just the code, without formatting (120 characters): int h=int.Parse(a[0]);for(int n=1;n<h+2;n++)Console.WriteLine(n<=h?new String('*',n*2-1).PadLeft(h+n):"*".PadLeft(h+1));  Version with 109 characters (just the code): for(int i=1,n=int.Parse(a[0]);i<n+2;i++)Console.WriteLine(new String('*',(i*2-1)%(n*2)).PadLeft((n+(i-1)%n)));  Result for height = 10:  * *** ***** ******* ********* *********** ************* *************** ***************** ******************* *  python, "-c" trick... @61 chars (and one line) python -c"for i in range($1)+[0]:print' '*($1-i)+'*'*(2*i+1)"  • Actually, it's 57 characters, only the ' ' space is significant as per the question specifications. – tzot Dec 27, 2008 at 15:05 ### Language: dc (through shell) Char count: 83 A little bit shorter dc version: dc -e '?d1rdsv[d32r[[rdPr1-d0<a]dsaxszsz]dsbx1-rd42rlbx2+r10Plv1-dsv0<c]dscxszsz32rlbx[*]p' <<<$1


EDIT: changed constant 10 into $1 • Good lord, what the hell is that? – amischiefr Aug 6, 2009 at 18:34 • Just read man page ;-) – Hynek -Pichi- Vychodil Aug 8, 2009 at 5:54 Here's a reasonably space-efficient Haskell version, at 107 characters: main=interact$(\g->unlines$map(\a->replicate(g-a)' '++replicate(a*2-1)'*')$[1..g]++[1]).(read::[Char]->Int)


running it:

$echo 6 | runhaskell tree.hs * *** ***** ******* ********* *********** *  Merry Christmas, all :) ### Language: dc (through shell), Char count: 119 (1 significant space) Just for the obscurity of it :) dc -e "$1dsnsm"'
[[ ]n]ss
[[*]n]st
[[
]n]sl
[s2s1[l2xl11-ds10<T]dsTx]sR
[lndlslRxlcdltlRxllx2+sc1-dsn0<M]sM
1sclMxlmlslRxltxllx
'

print ('*'*(2*i+1)).center(2*$1) "  I learned the center function and that "python -c" can accept more than one line code. Thanks, ΤΖΩΤΖΙΟΥ. ## C# using Linq:  using System; using System.Linq; class Program { static void Main(string[] args) { int n = int.Parse(args[0]); int i=0; Console.Write("{0}\n{1}", string.Join("\n", new int[n].Select(r => new string('*',i * 2 + 1) .PadLeft(n+i++)).ToArray()),"*".PadLeft(n)); } }  170 charcters. int n=int.Parse(a[0]);int i=0;Console.Write("{0}\n{1}",string.Join("\n",Enumerable.Repeat(0,n).Select(r=>new string('*',i*2+1).PadLeft(n+i++)).ToArray()),"*".PadLeft(n));  AWK, 86 characters on one line. awk '{s="#";for(i=0;i<$1;i++){printf"%"$1-i"s%s\n","",s;s=s"##"}printf"%"$1"s#\n",""}'

echo "8" | awk '{s="#";for(i=0;i<$1;i++){printf"%"$1-i"s%s\n","",s;s=s"##"}printf"%"$1"s#\n",""}' # ### ##### ####### ######### ########### ############# ############### # cat tree.txt 3 5 awk '{s="#";for(i=0;i<$1;i++){printf"%"$1-i"s%s\n","",s;s=s"##"}printf"%"$1"s#\n",""}' tree.txt
#
###
#####
#
#
###
#####
#######
#########
#


Language:PowerShell, Char count: 41 (including 1 space)

s="*"
for (( i=0; i<$n; i++ )); do printf "%$(($n+$i))s\n" "$s" s+="**" done printf "%$(($n))s\n" "*"  • Aug 22, 2019 at 14:34 ### Language: Python, Significant char count: 90 It's ugly but it works: import sys n=int(sys.argv[1]) print"\n".join(" "*(n-r-1)+"*"*(r*2+1)for r in range(n)+[0])  ... $ python tree.py 13
*
***
*****
*******
*********
***********
*************
***************
*****************
*******************
*********************
***********************
*************************
*

• Your character count is 98 (2 significant spaces, those in quotes)
– tzot
Dec 25, 2008 at 23:37

## J, 24

Works akin to the accepted answer in that you include the parameter in the source code. Expressing it as a proper function would be slightly longer. Uses a different approach than the accepted answer.

' *'#~(>:@+:,.~#-])0,~i.


E.g.

   ' *' #~ (>:@+: ,.~ #-]) 0 ,~ i.5
*
***
*****
*******
*********
*


As a function (27):

#&' *'@(>:@+:,.~#-])@,&0@i.


# c: 151116 115

Just giving it a whirl

i,j,a;main(c,v)int**v;{for(a=atoi(v[1]);i<a;i+=puts(""))for(j=0;j<a+i;)putchar(++j<a-i?32:42);printf("%*s",a,"*");}


i, j, a;
main(c, v) int **v; {
for (a = atoi(v[1]); i < a; i += puts(""))
for(j = 0; j < a + i;)
putchar(++j < a - i ? 32 : 42);
printf("%*s", a, "*");
}


Try it online!

# Code History:

main(int c, char **v){
int i, j, a = atoi(v[1]);
for (i = 1; i <= a; i++) {
for (j = 0; j < a + i - 1; j++)
putchar((j >= a - i) ? '*' : ' ');
putchar('\n');
}
printf("%*s*\n", a - 1, "");
}

• Welcome to Code Golf! This is good for a first submission; however, I see some easy improvements you can make by simply removing unnecessary spaces and newlines. Also, can you provide a link to test this? It's missing #include<stdio.h> and I'm getting segfaults: link Nov 8, 2019 at 15:12
• I think you're getting segfaults because you provided the number as an input rather than an argument link You also don't have to include the #include the compiler will yell at you but it will work. I left in the spaces because the challenge said to count characters ignoring whitespace and it makes it more readable Nov 8, 2019 at 18:48
• Oh okay. That makes sense, sorry not a C user :P Thanks for the explanation. And yeah, my bad, I forgot about that part of this challenge (haven't visited it in a while). Nov 8, 2019 at 19:12
• You can save another byte with ++j<a-i
– Jo King
Nov 13, 2019 at 1:33

# Poetic, 547 bytes

the triangle trees
a december i loved
o,i placed a fun christmasy thing
i know i am hoping on a santa,a gift,cookie plates,or bag o dolls
i know i am choosing my toy to expect of him,Mr.Claus
i say,Mr,i think i may ask nicely
we are nice people,we are
o,under the tree i go crazy as i glance at the a-b-c puzzle we got
a thing on Xmas i am happy to be toying with
o,i found it!for a moment,i shouted thanks
a gift i am having as we enjoy a holiday feast
and now i sleep
oh,here i am,silent as i could
i quickly awaken
i then go to locate a present


Try it online!

Translated from a version by Daniel Cristofani, but optimized specifically for program length in Poetic (more groups of > than <, more groups of + than -, etc).