Fibonacci With Case

fib(){ case $1 in 0)echo 0;;1)echo 1;;[0-9]*)echo $[$(fib $[$1-2])+$(fib $[$1-1])];;*)exit 1;;esac;}
Returns the '$1'th Fibonacci number.
Sample Output
$ fib 2
1
$

2
By: kzh
2010-06-28 19:41:44

What Others Think

recursively finding fibonacci sequences is a really good way to freeze any system up use a for loop for a more efficient calculation
amanharan · 433 weeks and 5 days ago
If one were worried about efficiency, then one should not use a shell script. This was quick to write. Thanks for the input.
kzh · 433 weeks and 5 days ago
fib(){ k=0; l=1; for i in `seq 1 $1`; do t=$l; l=$(($l + $k)); k=$t; done; echo $k;} also quick to write, but much faster
fpunktk · 433 weeks and 5 days ago
fpunktk: 93th and some others afterwards are negative, why is that?
alperyilmaz · 433 weeks and 5 days ago
I had never really used bash case statements before and was trying them out. If I really wanted to use large numbers, I would have done: python -c 'def fib(n): if n not in fibs:fibs[n]=fib(n-1)+fib(n-2) return fibs[n] import sys;fibs={0:0,1:1};print fib(int(sys.argv[1]))' 7 13
kzh · 433 weeks and 4 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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