TechQA.

Code-golf: Output multiplication table to the Console

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I recently pointed a student doing work experience to an article about dumping a multiplication table to the console. It used a nested for loop and multiplied the step value of each.

This looked like a .NET 2.0 approach. I was wondering, with the use of Linq and extension methods,for example, how many lines of code it would take to achieve the same result.

Is the stackoverflow community up to the challenge?

The challenge: In a console application, write code to generate a table like this example:

01 02 03 04 05 06 07 08 09
02 04 06 08 10 12 14 16 18
03 06 09 12 15 18 21 24 27
04 08 12 16 20 24 28 32 36
05 10 15 20 25 30 35 40 45
06 12 18 24 30 36 42 48 54
07 14 21 28 35 42 49 56 63
08 16 24 32 40 48 56 64 72
09 18 27 36 45 54 63 72 81

As this turned into a language-agnostic code-golf battle, I'll go with the communities decision about which is the best solution for the accepted answer.

There's been alot of talk about the spec and the format that the table should be in, I purposefully added the 00 format but the double new-line was originally only there because I didn't know how to format the text when creating the post!

language-agnostic code-golf rosetta-stone
Original Q&A
40

There are 40 answers

16
MPelletier On BEST ANSWER

J - 8 chars - 24 chars for proper format

*/~1+i.9

Gives:

1  2  3  4  5  6  7  8  9
2  4  6  8 10 12 14 16 18
3  6  9 12 15 18 21 24 27
4  8 12 16 20 24 28 32 36
5 10 15 20 25 30 35 40 45
6 12 18 24 30 36 42 48 54
7 14 21 28 35 42 49 56 63
8 16 24 32 40 48 56 64 72
9 18 27 36 45 54 63 72 81

This solution found by @earl:

'r(0)q( )3.'8!:2*/~1+i.9

Gives:

01 02 03 04 05 06 07 08 09 
02 04 06 08 10 12 14 16 18 
03 06 09 12 15 18 21 24 27 
04 08 12 16 20 24 28 32 36 
05 10 15 20 25 30 35 40 45 
06 12 18 24 30 36 42 48 54 
07 14 21 28 35 42 49 56 63 
08 16 24 32 40 48 56 64 72 
09 18 27 36 45 54 63 72 81
2
Callum Rogers On

Repent, 11, 10 chars

↓1⇄.⇄^↓↻*;

This is using my own toy language stack-based language Repent (which I will release soon, once it is up to scratch). I am sad to see J beating it, because I designed it only to beat J, Perl and Golfscript at code golf.

V_1v.v^↓↻*;

Interpreter (Alpha)

Language Reference (Alpha)

8
Nabb On

Brainf**k - 185 chars

>---------[++++++++++>---------[+<[-<+>>+++++++++[->+>>---------[>-<++++++++++<]<[>]>>+<<<<]>[-<+>]<---------<]<[->+<]>>>>++++[-<++++>]<[->++>+++>+++<<<]>>>[.[-]<]<]++++++++++.[-<->]<+]
0
Jesper Palm On

C# using aggregate, 118 characters

var r=Enumerable.Range(1,9).ToList();
r.ForEach(i=>Console.WriteLine(r.Aggregate("",(a,b)=>a+=(i*b).ToString("00 "))));
20
Matthew Whited On

C# - 117, 113, 99, 96, 95 89 characters

updated based on NickLarsen's idea

for(int x=0,y;++x<10;)
    for(y=x;y<x*10;y+=x)
        Console.Write(y.ToString(y<x*9?"00 ":"00 \n"));

99, 85, 82 81 characters ... If you don't care about the leading zeros and would allow tabs for alignment. 

for(int x=0,y;++x<10;)
{
    var w="";
    for(y=1;++y<10;)
        w+=x*y+"    ";
    Console.WriteLine(w);
}
0
dreamlax On

C - 97 79 characters

#define f(i){int i=0;while(i++<9)
main()f(x)f(y)printf("%.2d ",x*y);puts("");}}
1
John La Rooy On

Fortran95 - 40 chars (beating perl by 4 chars!)

This solution does print the leading zeros as per the spec.

print"(9(i3.2))",((i*j,i=1,9),j=1,9);end
4
John La Rooy On

C - 66 Chars

This resolves the complaint about the second parameter of main :)

main(x){for(x=8;x++<89;)printf("%.2d%c",x/9*(x%9+1),x%9<8?32:10);}

C - 77 chars

Based on dreamlax's 97 char answer. His current answer somewhat resembles this one now :)

Compiles ok with gcc, and main(x,y) is fair game for golf i reckon

#define f(i){for(i=0;i++<9;)
main(x,y)f(x)f(y)printf("%.2d ",x*y);puts("");}}
2
John La Rooy On

Python - 61 chars

r=range(1,10)
for y in r:print"%02d "*9%tuple(y*x for x in r)
1
Kevin Vaughan On

PHP, 71 chars

for($x=0;++$x<10;print"\n"){for($y=0;++$y<10;){printf("%02d ",$x*$y);}}

Output:

$ php -r 'for($x=0;++$x<10;print"\n"){for($y=0;++$y<10;){printf("%02d ",$x*$y);}}'
01 02 03 04 05 06 07 08 09 
02 04 06 08 10 12 14 16 18 
03 06 09 12 15 18 21 24 27 
04 08 12 16 20 24 28 32 36 
05 10 15 20 25 30 35 40 45 
06 12 18 24 30 36 42 48 54 
07 14 21 28 35 42 49 56 63 
08 16 24 32 40 48 56 64 72 
09 18 27 36 45 54 63 72 81
0
Landei On

Scala - 77 59 58 chars

print(1 to 9 map(p=>1 to 9 map(q=>"%02d "format(p*q))mkString)mkString("\n"))

Sorry, I had to do this, the Scala solution by Malax was way too readable...

[Edit] For comprehension seems to be the better choice:

for(p<-1 to 9;q<-{println;1 to 9})print("%02d "format p*q)

[Edit] A much longer solution, but without multiplication, and much more obfuscated:

val s=(1 to 9).toSeq
(s:\s){(p,q)=>println(q.map("%02d "format _)mkString)
q zip(s)map(t=>t._1+t._2)}
0
Oliver Hallam On

XQuery 1.0 (96 bytes)

string-join(for$x in 1 to 9 return(for$y in 1 to 9 return concat(0[$x*$y<10],$x*$y,' '),'

'),'')

Run (with XQSharp) with:

xquery table.xq !method=text
2
Oliver On

Not really a one-liner, but the shortest linq i can think of:

var r = Enumerable.Range(1, 9);
foreach (var z in r.Select(n => r.Select(m => n * m)).Select(a => a.Select(b => b.ToString("00 "))))
{
    foreach (var q in z)
        Console.Write(q);
    Console.WriteLine();
}

In response to combining this and SRuly's answer

Enumberable.Range(1,9).ToList.ForEach(n => Enumberable.Range(1,9).ToList.ForEach(n2 => Console.Write((n * n2).ToString("00 "))); Console.WriteLine(); });

9
Sruly On

C#

This is only 2 lines. It uses lambdas not extension methods

 var nums = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
 nums.ForEach(n => { nums.ForEach(n2 => Console.Write((n * n2).ToString("00 "))); Console.WriteLine(); });

and of course it could be done in one long unreadable line

 new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 }.ForEach(n => { new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9 }.ForEach(n2 => Console.Write((n * n2).ToString("00 "))); Console.WriteLine(); });

all of this is assuming you consider a labmda one line?

2
AudioBubble On

Oracle SQL, 103 characters:

select n, n*2, n*3, n*4, n*5, n*6, n*7, n*8, n*9 from (select rownum n from dual CONNECT BY LEVEL < 10)
1
Jonas Elfström On

Ruby, 49 chars

1.upto(9){|n|puts"%02d "*9%(n..81).step(n).to_a}

PS. With Wolfram Alpha it's 23 characters DS.

0
Glen Solsberry On

PHP, 62 chars

for(;$x++<9;print"\n",$y=0)while($y++<9)printf("%02d ",$x*$y);
5
BalusC On

Java - 155 137 chars

  • Update 1: replaced string building by direct printing. Saved 18 chars.
class M{public static void main(String[]a){for(int x,y=0,z=10;++y<z;System.out.println())for(x=0;++x<z;System.out.printf("%02d ",x*y));}}

More readable format:

class M{
 public static void main(String[]a){
  for(int x,y=0,z=10;++y<z;System.out.println())
   for(x=0;++x<z;System.out.printf("%02d ",x*y));
 }
}
0
cirons42 On

Haskell (not list comprehensions) 71 after import

It's a shame haskell doesn't have printf in it's prelude library but after importing in ghci 71 chars,the other haskell program was using list comprehensions:

Prelude> :module Text.Printf
Prelude Text.Printf> let r=[1..9]
Prelude Text.Printf> mapM_(\y->(mapM_(\x->printf"%02d "(x*y))r)>>(putStrLn ""))r
01 02 03 04 05 06 07 08 09
02 04 06 08 10 12 14 16 18
03 06 09 12 15 18 21 24 27
04 08 12 16 20 24 28 32 36
05 10 15 20 25 30 35 40 45
06 12 18 24 30 36 42 48 54
07 14 21 28 35 42 49 56 63
08 16 24 32 40 48 56 64 72
09 18 27 36 45 54 63 72 81
0
zwol On

R (very similar to Matlab on this level): 12 characters.

> 1:9%*%t(1:9)
     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
[1,]    1    2    3    4    5    6    7    8    9
[2,]    2    4    6    8   10   12   14   16   18
[3,]    3    6    9   12   15   18   21   24   27
[4,]    4    8   12   16   20   24   28   32   36
[5,]    5   10   15   20   25   30   35   40   45
[6,]    6   12   18   24   30   36   42   48   54
[7,]    7   14   21   28   35   42   49   56   63
[8,]    8   16   24   32   40   48   56   64   72
[9,]    9   18   27   36   45   54   63   72   81
0
Topera On

JavaScript - with console - 65 chars

for(i=0,a='';++i<10;a+='\n')for(j=0;++j<10;a+=i*j);console.log(a)

JavaScript - with html - 68 chars

for(i=0,a='';++i<10;a+='\n')for(j=0;++j<10;a+=i*j);document.write(a)
0
cthom06 On

Bash, 59 chars

for i in `seq 9`;do seq -w $i $i 99|sed 9q;done|column -c80
01  02  03  04  05  06  07  08  09
02  04  06  08  10  12  14  16  18
03  06  09  12  15  18  21  24  27
04  08  12  16  20  24  28  32  36
05  10  15  20  25  30  35  40  45
06  12  18  24  30  36  42  48  54
07  14  21  28  35  42  49  56  63
08  16  24  32  40  48  56  64  72
09  18  27  36  45  54  63  72  81
0
Lai Jiangshan On

BASH 53

for((i=1;i<10;i++));do seq -s' ' $i $i $((9*i));done
0
AudioBubble On

C++ RANKING IN AT 99999TH PLACE (76 chars) 

for(int i=1;i<=9;++i){cout<<i<<" "<<i+1<<i+2<<i+3<<i+4<<i+5<<i+6<<i+7<<i+8;}
3
John La Rooy On

COBOL - 218 chars -> 216 chars

PROGRAM-ID.P.DATA DIVISION.WORKING-STORAGE SECTION.
1 I PIC 9.
1 N PIC 99.
PROCEDURE DIVISION.PERFORM 9 TIMES
ADD 1 TO I
SET N TO I
PERFORM 9 TIMES
DISPLAY N' 'NO ADVANCING
ADD I TO N
END-PERFORM
DISPLAY''
END-PERFORM.

Edit

216 chars (probably a different compiler)

PROGRAM-ID.P.DATA DIVISION.WORKING-STORAGE SECTION.
1 I PIC 9.
1 N PIC 99.
PROCEDURE DIVISION.

  PERFORM B 9 TIMES
  STOP RUN.

B.
 ADD 1 TO I
 set N to I
 PERFORM C 9 TIMES
 DISPLAY''.

C.
 DISPLAY N" "NO ADVANCING
 Add I TO N.
4
earl On

K - 12 characters

Let's take the rosetta-stoning seriously, and compare Kdb+'s K4 with the canonical J solution (*/~1+i.9):

  a*/:\:a:1+!9
1 2  3  4  5  6  7  8  9 
2 4  6  8  10 12 14 16 18
3 6  9  12 15 18 21 24 27
4 8  12 16 20 24 28 32 36
5 10 15 20 25 30 35 40 45
6 12 18 24 30 36 42 48 54
7 14 21 28 35 42 49 56 63
8 16 24 32 40 48 56 64 72
9 18 27 36 45 54 63 72 81

J's "table" operator (/) equals the K "each-left each-right" (/:\:) idiom. We don't have J's extremely handy "reflexive" operator (~) in K, so we have to pass a as both left and right argument.

5
gnovice On

MATLAB - 10 characters

a=1:9;a'*a

... or 33 characters for stricter output format

a=1:9;disp(num2str(a'*a,'%.2d '))
1
Rafe On

C#, 135 chars, nice and clean:

var rg = Enumerable.Range(1, 9);
foreach (var rc in from r in rg 
                   from c in rg 
                   select (r * c).ToString("D2") + (c == 9 ? "\n\n" : " "))
    Console.Write(rc);
0
Brian On

F# - 61 chars:

for y=1 to 9 do(for x=1 to 9 do printf"%02d "(x*y));printfn""

If you prefer a more applicative/LINQ-y solution, then in 72 chars:

[1..9]|>Seq.iter(fun y->[1..9]|>Seq.iter((*)y>>printf"%02d ");printfn"")
1
Joey Adams On

PostgreSQL: 81 74 chars

select array(select generate_series(1,9)*x)from generate_series(1,9)as x;
4
John La Rooy On

Ruby - 42 Chars (including one linebreak, interactive command line only)

This method is two lines of input and only works in irb (because irb gives us _), but shortens the previous method by a scant 2 charcters.

1..9
_.map{|y|puts"%02d "*9%_.map{|x|x*y}}

Ruby - 44 Chars (tied with perl)

(a=1..9).map{|y|puts"%02d "*9%a.map{|x|x*y}}

Ruby - 46 Chars

9.times{|y|puts"%02d "*9%(1..9).map{|x|x*y+x}}

Ruby - 47 Chars

And back to a double loop

(1..9).map{|y|puts"%02d "*9%(1..9).map{|x|x*y}}

Ruby - 54 chars!

Using a single loop saves a couple of chars!

(9..89).map{|n|print"%02d "%(n/9*(x=n%9+1))+"\n"*(x/9)}

Ruby - 56 chars

9.times{|x|puts (1..9).map{|y|"%.2d"%(y+x*y)}.join(" ")}
0
robbles On

Ruby - 56 chars :D

9.times{|a|9.times{|b|print"%02d "%((a+1)*(b+1))};puts;}
0
Felix Ungman On

Another attempt using C#/Linq with GroupJoin:

Console.Write(
    String.Join(
        Environment.NewLine,
        Enumerable.Range(1, 9)
            .GroupJoin(Enumerable.Range(1, 9), y => 0, x => 0, (y, xx) => String.Join(" ", xx.Select(x => x * y)))
            .ToArray()));
4
hobbs On

Perl, 44 chars

(No hope of coming anywhere near J, but languages with matrix ops are in a class of their own here...)

for$n(1..9){printf"%3d"x9 .$/,map$n*$_,1..9}
2
jtbandes On

Ruby — 47 chars

puts (a=1..9).map{|i|a.map{|j|"%2d"%(j*i)}*" "}

Output

 1  2  3  4  5  6  7  8  9
 2  4  6  8 10 12 14 16 18
 3  6  9 12 15 18 21 24 27
 4  8 12 16 20 24 28 32 36
 5 10 15 20 25 30 35 40 45
 6 12 18 24 30 36 42 48 54
 7 14 21 28 35 42 49 56 63
 8 16 24 32 40 48 56 64 72
 9 18 27 36 45 54 63 72 81

(If we ignore spacing, it becomes 39: puts (a=1..9).map{|i|a.map{|j|j*i}*" "} And anyway, I feel like there's a bit of room for improvement with the wordy map stuff.)

0
Vatine On

Common Lisp, 79 characters (including whitespace):

(dotimes (i 9) (dotimes (j 9) (format t "~2,'0d " (* (1+ i) (1+ j)))) (terpri))

With something approaching a more traditional formatting:

(dotimes (i 9) 
  (dotimes (j 9) 
    (format t "~2,'0d " (* (1+ i) (1+ j)))) 
  (terpri))

Then there's a 106-character version showing off the power of the formatter:

(format t "~{~{~2,'0d~^ ~}~%~}"
        (loop for i from 1 to 9 
           collect (loop for j from 1 to 9 
                      collect (* i j))))
0
AudioBubble On

PHP, 67 characters

while(++$x<10){$y=0;while(++$y<10)printf("%02d ",$x*$y);print"\n";}
2
Thomas On

cat - 252 characters

01 02 03 04 05 06 07 08 09

02 04 06 08 10 12 14 16 18

03 06 09 12 15 18 21 24 27

04 08 12 16 20 24 28 32 36

05 10 15 20 25 30 35 40 45

06 12 18 24 30 36 42 48 54

07 14 21 28 35 42 49 56 63

08 16 24 32 40 48 56 64 72

09 18 27 36 45 54 63 72 81

Assuming that a trailing newline is wanted; otherwise, 251 chars.

* runs *

4
kennytm On

Haskell — 85 84 79 chars

r=[1..9]
s x=['0'|x<=9]++show x
main=mapM putStrLn[unwords[s$x*y|x<-r]|y<-r]

If double spacing is required (89 81 chars),

r=[1..9]
s x=['0'|x<=9]++show x
main=mapM putStrLn['\n':unwords[s$x*y|x<-r]|y<-r]
0
CaffGeek On

c# - 125, 123 chars (2 lines):

var r=Enumerable.Range(1,9).ToList();
r.ForEach(n=>{var s="";r.ForEach(m=>s+=(n*m).ToString("00 "));Console.WriteLine(s);});

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