General :: Running Executable In Bash Script

I've been trying to write a bash script called runSorter.sh that runs an executable that also takes in some parameters and outputs the results to a text file. The executable, sorter, takes in a number parameter. I want to make it so that you can input as many number parameters into runSorter.sh as you want and it will run the sorter executable for each one. So far, what I have looks like this:

#!/bin/bash
args=("$@")
INDEX=0
if [ -z args ]; then
echo "Error"
else
while [ $# -gt $INDEX ]; do
NUM=${args[$INDEX]}
echo $NUM
echo ./sorter $NUM
let INDEX=INDEX+1
done
fi

My problem is that when I run ./run-sorter.sh 100 on my terminal, it just prints this to the screen:
./sorter 100
How can I have so that it properly executes sorter and outputs everything to a text file?