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Dividing by zero

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# 1  
Old 08-26-2013
Dividing by zero
Does anyone know how to include as a script maybe an "echo" warning that explains that if a user uses the second number "zero" when dividing, that the result will BE "zero."

I need, example: 5/0 (second number) = 0, in script form.

current script:
Code:
echo "Enter a number"
read num1
echo "Enter another number"
read num2
div=$(num1 /num2)
echo "div=$div"

thanks,
joe.
Last edited by Scott; 08-26-2013 at 02:24 PM.. Reason: Please use code tags
# 2  
Old 08-26-2013
You should do some 'sanity checking' on the value of your variables before making the calculation.

Besides that, the shell won't do precision arithmetic - you will always end up with an integer.

i.e.
Code:
echo $((5/-2))
-2

# 3  
Old 08-26-2013
I *ONCE* ran echo $(($NUM/0))... needless to say it was the last time we ever saw that server.

Joke aside, I agree the only way to do this is with some validation before the actual division operation happens.

Take a look at bc if you need a more robust solution.
Last edited by verdepollo; 09-02-2013 at 02:41 AM..
This User Gave Thanks to verdepollo For This Post:
Aia
# 4  
Old 08-26-2013
A quicky from the interactive shell...
You will have to intercept the value 0 and generate your own error report, although the shell will generate its own...

Code:
Last login: Mon Aug 26 19:05:46 on console
AMIGA:barrywalker~> x=11
AMIGA:barrywalker~> y=3
AMIGA:barrywalker~> echo $((x/y)) # Integer result only...
3
AMIGA:barrywalker~> echo $((x%y)) # However the remainder is...
2
AMIGA:barrywalker~> x=9
AMIGA:barrywalker~> y=0
AMIGA:barrywalker~> echo $((x/y)) # Integer result only...
-bash: x/y: division by 0 (error token is "y")
AMIGA:barrywalker~> x=11
AMIGA:barrywalker~> y=3
AMIGA:barrywalker~> echo "Number = $((x/y))+$((x%y))/$y in fractions..."
Number = 3+2/3 in fractions...
AMIGA:barrywalker~> _

Last edited by wisecracker; 08-26-2013 at 04:08 PM.. Reason: Added fraction bit...
# 5  
Old 08-26-2013
Thanks...
...Thank you all. And thank you, "verdepollo." I should have thought about your suggestion.

joe.
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