Middle three digits: Difference between revisions

=={{header|UNIX Shell}}==

{{works with|Bourne Again Shell}}

<lang bash>function middle3digits

{

local -i n="${1#-}"

local -i l=${#n}

if (( l < 3 )); then

echo "$0: $1 has less than 3 digits" 1>&2

return 1

elif (( l % 2 == 0 )); then

echo "$0: $1 has an even number of digits" 1>&2

return 1

else

echo ${n:$((l/2-1)):3}

return 0

fi

}

# test

testdata=(123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345 1 2 -1

-10 2002 -2002 0)

for n in ${testdata[@]}; do

printf "%10d: " $n

middle3digits "$n"

done</lang>

Output: <pre> 123: 123

12345: 234

1234567: 345

987654321: 654

10001: 000

-10001: 000

-123: 123

-100: 100

100: 100

-12345: 234

1: ./mid3: 1 has less than 3 digits

2: ./mid3: 2 has less than 3 digits

-1: ./mid3: -1 has less than 3 digits

-10: ./mid3: -10 has less than 3 digits

2002: ./mid3: 2002 has an even number of digits

-2002: ./mid3: -2002 has an even number of digits

0: ./mid3: 0 has less than 3 digits</pre>