Problem with shell script, laying in if/then/else & Case structure[SIMPLE MATH PROB.]

charging-ibis · 01-05-2013, 12:08 PM

Hello linux users. I am studying for my Linux+ exam. I am on an exersice on doing a simple math problem w/ a desicion of calculating the sum or average of 3 numbers entered by the user. Everything is fine in the code until it steps through the case structure. I even had the same problems using the if/then/else. Here is my code:

Code:

#!/bin/bash
### The Name of the file is 'domath0' ###
clear
declare -i A
declare -i B
declare -i C
declare -i ANSWER
echo "Enter #1:"
read A
echo "Enter #2:"
read B
echo "Enter #3:"
read C
echo "Choose Process:"
echo "p : the sum"
echo "v : the average:"
echo "What is your decision?: "
read CHOICE
case $CHOICE in
	p | P ) ANSWER = A + B + C ##Here is line 19##
;;
	v | V ) ANSWER = A + B + C
	ANSWER = $ANSWER / 3
;;
esac
echo "The result is: " $ANSWER "." ## Here is line 25##
exit 0

Now here is the execution/output from shell:

Code:

Enter #1:
1
Enter #2:
2
Enter #3:
3
Choose Process:
p : the sum
v : the average:
What is your decision?: 
p
/home/cbattle4654/bin/domath0: line 19: ANSWER: command not found
The result is:  .

As a result also, output of line 25 is absent.
I would like to understand what is going on. Am I doing something that I am not seeing? Please clarify with me as soon as possible.
~Thanks

druuna · 01-05-2013, 12:53 PM

You almost had it:

Code:

case $CHOICE in
    p | P ) (( ANSWER = A + B + C ))
;;
    v | V ) (( ANSWER = A + B + C ))
    (( ANSWER = ANSWER / 3 )) # $ also removed

This is arithmetic and you need to use double parentheses.

Bash Arithmetic Expression

charging-ibis · 01-05-2013, 07:11 PM

Quote:

Originally Posted by druuna

You almost had it:

Code:

case $CHOICE in
    p | P ) (( ANSWER = A + B + C ))
;;
    v | V ) (( ANSWER = A + B + C ))
    (( ANSWER = ANSWER / 3 )) # $ also removed

This is arithmetic and you need to use double parentheses.

Bash Arithmetic Expression

Oh my goodness thanks for your help I also read the simple arithmetic expressions that you referred me to and I can grow from this. I thank you.