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Fibonacci numbers with awk

Terminal - Fibonacci numbers with awk
awk 'func f(n){return(n<2?n:f(n-1)+f(n-2))}BEGIN{while(a<24){print f(a++)}}'
2010-11-24 10:40:08
User: unefunge
Functions: awk
4
Up
Down
Fibonacci numbers with awk

recursive version, "pure" AWK

Show sample output | Add to favourites | Report as malicious

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
seq 50| awk 'BEGIN {a=1; b=1} {print a; c=a+b; a=b; b=c}'
2009-03-24 20:39:24
User: kaan
Functions: awk seq
Tags: awk seq
13
Up
Down
Fibonacci numbers with awk

Another combination of seq and awk. Not very efficient, but sufficiently quick.

Show sample output | Comments (1) | Add to favourites | Report as malicious
awk 'BEGIN {a=1;b=1;for(i=0;i<'${NUM}';i++){print a;c=a+b;a=b;b=c}}'
2009-09-06 03:05:55
User: arcege
Functions: awk
Tags: awk
0
Up
Down
Fibonacci numbers with awk

Does not require input to function or complete. Number of iterations controlled by shell variable $NUM.

Show sample output | Comments (1) | Add to favourites | Report as malicious
prev=0;next=1;echo $prev;while(true);do echo $next;sum=$(($prev+$next));prev=$next;next=$sum;sleep 1;done
2009-09-06 09:38:10
User: sharfah
Functions: echo
0
Up
Down
Fibonacci numbers with sh
Comments (1) | Add to favourites | Report as malicious
gawk '{n=$1;a=0;b=1;c=1;for(i=1;i<n;i++){c=a+b;a=b;b=c};print c}' << eof
2010-11-26 08:36:30
User: unixmonkey13930
Functions: gawk
Tags: awk
-5
Up
Down
Fibonacci numbers with awk

only take the first field on each row to compute the fibo on this number

Show sample output | Comments (0) | Add to favourites | Report as malicious

Know a better way?

If you can do better, submit your command here.

What others think

Recursion: Pretty much always the wrong way to do something.

Unless you're using a compiler on it before you run it, it will almost certainly be massively slower than a loop that does the same thing. Even with a compiler it's not a certainty you'll achieve comparable speeds.

This, for instance, is 30x slower than http://www.commandlinefu.com/commands/view/1654/fibonacci-numbers-with-awk

Comment by TheMightyBuzzard 130 weeks ago

who cares? It's elegant. If you really need speed you know where to find a C compiler ;-)

Comment by unefunge 130 weeks ago

Your point of view

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