ksh mutliply 0.2 constant with value and output

[Susan Prosser]

Please can someone tell me what I am doing wrong!!

I want to mulitply a VALUE=100
with a CONSTANT=0.02 and display the results with decimal places.

If I try ...

(( NUM = 100 * 0.2 ))
printf "Answer is %4.2f\n" , $NUM

The result comes back as
Answer is 44.00
Answer is 0.00

Any ideas
Thanks

when I am want 20

[Joseph C. Denman]

Try:

NUM=`expr 100 \* 2 / 10`
printf "Answer is %4.2f\n" , $NUM

Hope this helps.

...jcd...

[Robin Wakefield · Accepted solution]

Kevin,

(( .... )) syntax is integer only.

Use something like bc:

# echo "100*0.2" | bc | read NUM
# printf "%4.2f\n" $NUM
20.00

Rgds, Robin

[Tom Maloy]

The comma is causing the second line of output. Without the comma, just get 0.00.

ksh does integer arithmetic. 0.2 rounds to integer 0, so the multiplication produces 0.

Can you do

(( NUM = 100 * 2 / 10 ))

This will produce 20.

Tom

[Hai Nguyen_1]

Kevin,

Try this simple awk command:

# echo | awk '{print 100 * 0.2}'

Hai

[Joseph C. Denman]

Kevin,

Robin is correct. You will need to use something like bc.

My above example, though produces the correct output for the example, will give an incorrect response in the event of a fraction.

...jcd...