Question

This is my first time using Bash, so bear with me. I’m using Git Bash in Windows for a college project, trying to rewrite some C code that provides an alternate way of multiplying two numbers “a” and “b” to produce “c”. This is what I came up with:

#!/bin/bash

declare -i a
declare -i b
declare -i c=0
declare -i i=0    # not sure if i have to initialize this as 0?
echo "Please enter a number: "
read a
echo "Please enter a number: "
read b

for i in {1..b}
do
    let "c += a"
done

echo "$a x $b = $c"

I think part of the problem is in the for loop, that it only executes once. This is my first time using Bash, and if anyone could find the fault in my knowledge, that would be all I need.

Answer 1

for i in {1..b}

won’t work, because ‘b’ isn’t interpreted as a variable but a character to iterate to.
For instance {a..c} expands to a b c.

To make the brace expansion work:
for i in $(eval echo “{1..$b}”)

The let “c += a” won’t work either.
let c+=$a might work, but I like ((c+=a)) better.

Another way is this:


for ((i = 1; i <= b; i++))
do
    ((c += a))
done


(might need to put #!/bin/bash at the top of your script, because sh does less than bash.)