floating point arithmetic with functions - bash

Question

What these functions do is they curl a json file and parse it, whose output is a number.
function func() {
curl -Ss -H 'Cache-Control: no-cache' url.com/A?limit=2 | jq -r '.
[] | .[] | .blah'
}
function func2() {
curl -Ss -H 'Cache-Control: no-cache' url.com/B2?limit=2 | jq -r '.
[] | .[] | .blah'
}
function func3() {
curl -Ss -H 'Cache-Control: no-cache' url.com/C3?limit=2 | jq -r '.
[] | .[] | .blah'
}
function example() {
"(($(func) * $(func2) * $(func3)))" | bc -l
}
#result is it echoing the numbers, but not actually doing the math.
#echoing .072*.027 in bc, but no math.
So what I'm trying to do is do floating point arithmetic through bash, this is going to be referenced through another function. The only difference is this is with functions. Bash doesn't support floating point arithmetic which is solved through bc.
Example Function numeric output:
#func output
0.072854 #A
0.072855 #B
0.072828 #C
0.072827 #D
#func2 output
0.027873 #A
0.027884 #B
0.027848 #C
0.027847 #D
#func3 output
0.383170 #A
0.383215 #B
0.381858 #C
0.381857 #D
How it works, A * A * A = output1, B * B * B = output2, C * C * C = ouput3
What I've Tried:
function blah() {
echo $((func*func2*func3)) | bc -l
}
#result is "0"
echo "$(func) * $(func2) * $(func3)" | bc -l
#result is:
.072965
.072966
.072925
.002030350008
.027856
.027827
.010633768950
.382371
.380995
.380977

Answer 1

I believe you'll want your function to be like this:
echo "$(func) * $(func2) * $(func3)" | bc -l
EDIT: Since you have multiple values that are output you could put them into arrays, then loop through them and multiply the values:
example() {
a=($(func1))
b=($(func2))
c=($(func3))
for i in {0..3} # set to number of values returned
do
echo "${a[i]} * ${b[i]} * ${c[i]}" | bc -l
done
}
Based on your values the output should be:
.000778087816708140
.000778496988156300
.000774451610799552
.000774411139231933
If your func's return a value then using echo with bc with them should be sufficient.