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Full Discussion: Simple maths calculator loop.
Top Forums Shell Programming and Scripting Simple maths calculator loop. Post 302583063 by methyl on Monday 19th of December 2011 12:45:36 PM
Old 12-19-2011
Using as much of the orginal code as possible we can create a simple "while true loop around the decision whether to quit or do another calculation. We enter the value for $n1 once at the top of the script and from that point on seed $n1 with the value of a running total in $total.

Code:
echo "please enter a number"
read n1

total=0

while true
do
     echo "please choose an operation (or press c/r to exit)"
     echo "1. add"
     echo "2. subtract"
     echo "3. divide"
     echo "4. multiply"
     read opr
     # Exit if user pressed carriage-return
     if [ "${opr}""X" = "X" ]
     then
         break
     fi

     echo "please enter a number again"
     read n2
     # Do the calculation required
     if [ $opr = "1" ]
         then
              total=$((n1+n2))
         elif [ $opr = "2" ]
         then  
              total=$((n1-n2))
         elif [ $opr = "3" ]
         then
              total=$((n1/n2))
         elif [ $opr = "4" ]
         then
              total=$((n1*n2))
     fi
     # Display running total
     echo ""
     echo "     Running total: $total"
     echo ""
     # Seed $n1 with the current value of $total
     n1=$total 
done

The modified script keeps on asking for more calculation on the running total until the user presses carriage-return.
You could add a line just before "break" to display "Final total is $total" if that is a requirement.
Try it and enjoy.
Last edited by methyl; 12-19-2011 at 08:38 PM.. Reason: inconsistent f1 n1
 

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LEARN ABOUT FREEBSD

newkey

NEWKEY(8)						    BSD System Manager's Manual 						 NEWKEY(8)

NAME

     newkey -- create a new key in the publickey database

SYNOPSIS

     newkey -h hostname
     newkey -u username

DESCRIPTION

     The newkey utility is normally run by the network administrator on the Network Interface Service (NIS) master machine in order to establish
     public keys for users and super-users on the network.  These keys are needed for using secure RPC or secure NFS .

     The newkey utility will prompt for the login password of the given username and then create a new public/secret key pair in /etc/publickey
     encrypted with the login password of the given user.

     Use of this program is not required: users may create their own keys using chkey(1).

OPTIONS

     -h hostname
	     Create a new public key for the super-user at the given hostname.	Prompts for the root password of the given hostname.

     -u username
	     Create a new public key for the given username.  Prompts for the NIS password of the given username.

SEE ALSO

     chkey(1), keylogin(1), publickey(5), keyserv(8)

NOTES

     The Network Information Service (NIS) was formerly known as Sun Yellow Pages (YP).  The functionality of the two remains the same; only the
     name has changed.

BSD
								 October 12, 1987							       BSD
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