Arithmetic in floating point

Shell Programming and Scripting
1

is it not possible to simply di aritmetic without using bc or awk

i have tried folllowing operatrions but they support only integer types plz suggest me code for floating using values stored in the variables.the ans i get is integer and if i input floating values i get error numeric constant missing plz help

case $choice in

"1")
        add=`expr $a + $b`
        echo $add
        ;;

"2")
        sub=`expr $a - $b`
        echo $sub
        ;;

"3")

        mul=`expr $a \\* $b`
        echo $mul
        ;;
"4")
        div=`expr $a / $b`
        echo $div
        ;;

esac
2

You are correct - you need awk, perl, bc, etc. to do floating point arithmetic.
Not shell - shell does not support FP.

3 
add=`echo "scale=1; $a / $b " | bc`
4

thanks buddy
it is not possible with expr to get floating poin answers

5

Correct (it's not possible).

Some newer shells, like ksh93 support floating point arithmetic, but for portability it's probably best to use bc.

6

A challenge could be to write a shell script that performs FP arithmetics.

7

Depending on the fractional resolution you require you can scale up all the numbers and use the fixed-point arithmetics. Other than this - it's not possible to have FP in shell as FP instructions are not a must-have for a Unix system machine and shells should be as portable as possible. For same reason i.e. Linux kernel does not have any floating point operation as well.

frans:
Below script:

echo "1 / 2" | bc -l

is a valid shell script performing FP arithmetics. But I know what you meant. :wink: