using vi for scripting

ajjc2005 · 08-22-2012, 12:04 PM

I need to write a program that takes a number and shows the result of n!

Example: 5!=1*2*3*4*5

Thank you in advance for your help.

jkirchner · 08-22-2012, 12:16 PM

Hmmm, is this homework? If so, please post what you have done so far.

Also, VI is an editor, what programming language are you supposed to be writing this program in?

ajjc2005 · 08-22-2012, 12:23 PM

I'm not sure if I should be using if or a while loop or something else

echo "Please enter a number"
read num
count=0
total=0
if test $count -lt $num
then
let count=$count+1
let total=$num*$count
fi
echo $total

TB0ne · 08-22-2012, 01:35 PM

Quote:

Originally Posted by ajjc2005

I need to write a program that takes a number and shows the result of n!

Example: 5!=1*2*3*4*5

Thank you in advance for your help.

You don't have anything in your script to ask for a second (or subsequent) value. You should prompt the user for more input, and tell them something like "Press Z to multiply your values", so the user can decide when they're done. Something like this:

Code:

#!/bin/Bash
echo "Enter the numbers to be Multiplied:"
read n1
read n2
answer=`expr $n1 \* $n2`
echo $answer

...may give you an idea. It's only two variables now, but can be expanded.

WzJazz · 08-22-2012, 01:37 PM

Also, do a google search on factorial, factorial bash or factorial programming.

chrism01 · 08-22-2012, 06:03 PM

Hi TB0ne,
the OP is asking about factorial calcs https://en.wikipedia.org/wiki/Factorial, not just any multiplication set.

Vegan · 08-22-2012, 10:36 PM

Quote:

Originally Posted by ajjc2005

I'm not sure if I should be using if or a while loop or something else

echo "Please enter a number"
read num
count=0
total=0
if test $count -lt $num
then
let count=$count+1
let total=$num*$count
fi
echo $total

A while loop will be perfect for what you are trying to achieve

David the H. · 08-22-2012, 11:40 PM

I'm curious what you mean about "using vi", for scripting. As mentioned, vi is just a text editor. However it is possible to write scripted input for it to edit files automatically.

None of that has much to do with shell arithmetic, however. Probably the easiest way to do a factorial (assuming integer input, of course), is with a simple c-style for loop.

clocker · 08-23-2012, 08:13 AM

if you need help on using vi, i can help but otherwise you should put your thread on the programming forum.