Shell Programming and Scripting

Hello every body. I am trying to find the factorial using the following code. But it is giving the syntax error. I tried very much but in vain. Thanks in advance for helping me

factorial()
{
if [ $1 -gt 1 ]
then
y=`expr $1 - 1`
x=$(( $1 \* factorial $y ))
return $x
else
return 1
fi
}
echo -n "Enter number = "; read n
factorial $n

Hello every body. I am trying to find the factorial using the following code. But it is giving the syntax error. I tried very much but in vain. Thanks in advance for helping me

factorial()
{
if [ $1 -gt 1 ]
then
y=`expr $1 - 1`
x=$(( $1 \* factorial $y ))
return $x
else
return 1
fi
}
echo -n "Enter number = "; read n
factorial $n

HI,
I have made a small change in your code and it is working fine for me...try it...
factorial()
{
if [ $1 -gt 1 ]
then
y=`expr $1 - 1`
factorial $y
#x=$(( $1 \* factorial $y )) -- I have commented this
x=$(( $1 * $? ))
return $x
else
return 1
fi
}
echo -n "Enter number = "; read n
factorial $n
echo $?

Thanks
Raghuram

Thank u very much for the reply. Can u tell me the concept of $?. Thanks once again for great help because I was doing effort for last one day.

HI,
$? tells the return value of the last called function.
In that case it was the function call factorial().

Thanks
Raghuram

Hello,

As far as i know, recursive functions are not supported in Shell Scripting.
Anyways, the following script will help you to get the factorial of a number.

#! /bin/sh

echo "Enter a number: "
read num

i=2
res=1

if [ $num -ge 2 ]
then
while [ $i -le $num ]
do
res=`expr $res \* $i`
i=`expr $i + 1`
done
fi

echo "Factorial of $num = $res"

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