Example 2: Simple calculator and user interaction

#!/bin/bash

while [ -z $arg1 ] #will be repeated until a data will be entered

do

read p Enter argument1: arg1

done

while [ -z $arg2 ] #will be repeated until a data will be entered

do

read p Enter argument2: arg2

done

echo Youve entered: arg1=$arg1 and arg2=$arg2

let addition=arg1+arg2

let subtraction=arg1-arg2

let multiplication=arg1*arg2

let division=arg1 / arg2

let reminder=arg1 % arg2

echo e results:

echo $arg1+$arg2=$addition

echo $arg1-$arg2=$subtraction

echo $arg1*$arg2=$multiplication

echo $arg1/$arg2=($division+$reminder/$arg2)

3.1. (Script 1) You are supposed to MODIFY example script provided in the Example 2 so that it would perform operations +, -, *, / (only the whole part of the division operation, ignore the reminder part) and ^ (power). When it comes to the first four operations, they are normally supported by let command or the other alternative ways of calculating numerical expressions mentioned in the lecture slides (and these are actually already programmed in the Example 2). However, the power operation will need to be implemented by you, probably in the form of some sort of loop operations (I am leaving this to you to decide). Once you write the script, you will be required to upload it to the scriptcheck.cms.gre.ac.uk system for test purposes. The marking system will assume that the script will be processing three command line parameters, one for the first argument of arithmetic operation, the second command line parameter for the second argument of the arithmetic operations and third parameter expressing the arithmetic operation to be processed. Your script will be executed from the command line, for example, in order to check if your solution is correct it might be executed as: scriptname 4 2 operation The scriptcheck system will check if you script returns appropriate results for each operation; for the example execution parameters (4 and 2) it should return:

4 2 + -> 6

4 2 - -> 2

4 2 * -> 8

4 2 / -> 2

4 2 ^ -> 16