#!/bin/bash
# max2.sh: Maximum of two LARGE integers.

# This is the previous "max.sh" example,
#+ modified to permit comparing large integers.

EQUAL=0 # Return value if both params equal.
E_PARAM_ERR=-99999 # Not enough params passed to function.

max2 () # "Returns" larger of two numbers.
{
if [ -z "$2" ]
then
echo $E_PARAM_ERR
return
fi

if [ "$1" -eq "$2" ]
then
echo $EQUAL
return
else
if [ "$1" -gt "$2" ]
then
retval=$1
else
retval=$2
fi
fi

echo $retval # Echoes (to stdout), rather than returning value.

}


return_val=$(max2 33001 33997)
# This is actually a form of command substitution:
#+ treating a function as if it were a command,
#+ and assigning the stdout of the function to the variable 'return_val.'


# ========================= OUTPUT ========================
if [ "$return_val" -eq "$E_PARAM_ERR" ]
then
echo "Error in parameters passed to comparison function!"
elif [ "$return_val" -eq "$EQUAL" ]
then
echo "The two numbers are equal."
else
echo "The larger of the two numbers is $return_val."
fi
# =========================================================

exit 0

# Exercises:
# ---------
# 1) Find a more elegant way of testing
#+ the parameters passed to the function.
# 2) Simplify the if/then structure at "OUTPUT."
# 3) Rewrite the script to