Shell Programming and Scripting

#!/bin/bash
#
#
##Author: John Burmeister
##Version: Who cares.
 
shopt -s -o nounset
 
declare -i userResponse
declare -i testScore
main()
{
userPrompt
calculateGrade
}
 
userPrompt()
{
echo -e "Would you like to enter a test score? "
read userResponse
if [$userResponse = "y" -o $userResponse = "Y"]
then
calculateGrade
elif
exit
fi
}
calculateGrade()
{
echo -e "\nPlease enter a test score: "
read testScore
if [$testScore -gt 0 -a $testScore -lt 49]
then
echo -e "\nYou recieved an: F "
elif [$testScore -gt 49 -a $testScore -lt 59]
then
echo -e "\nYou received an: D "
elif [$testScore -gt 59 -a $testScore -lt 69]
then
echo -e "\nYou reveived a: C "
elif [$testScore -gt 69 -a $testScore -lt 79]
then
echo -e "\nYou received a: B "
elif [$testScore -gt 80 -a $testScore -le 100]
then
echo -e "\nYou received an: A "
fi
userPrompt
}

#! /bin/bash

# declare -i userResponse # If you typecast userResponse as an integer, then how will it hold "y" to imply yes!
# declare -i testScore # Don't typecast variables unless you really need to. Shell will take care of that by itself.
# What is main()??? This isn't C programming. main() would be treated as just another function.
# If you wish you can write a main() and call other functions from inside it, but remember to call "main()" from main!

calculateGrade()
{
echo -e "\nPlease enter a test score: "
read testScore
if [ $testScore -gt 0 -a $testScore -lt 49 ] # Put a space around square brackets.
then
    echo -e "\nYou recieved an: F "
elif [ $testScore -gt 49 -a $testScore -lt 59 ]
then
    echo -e "\nYou received an: D "
elif [ $testScore -gt 59 -a $testScore -lt 69 ]
then
    echo -e "\nYou reveived a: C "
elif [ $testScore -gt 69 -a $testScore -lt 79 ]
then
    echo -e "\nYou received a: B "
elif [ $testScore -gt 80 -a $testScore -le 100 ]
then
    echo -e "\nYou received an: A "
fi
userPrompt
}

userPrompt()
{
echo -e "Would you like to enter a test score? "
read userResponse
# Put a space around square brackets.
if [ $userResponse == "y" -o $userResponse == "Y" ] # A single = is an assignment operator not a relational operator. Use ==
then
    calculateGrade
else # Should be else here not elif
    exit
fi
}

# Call functions after you've defined them.
userPrompt
calculateGrade