Shell Programming and Scripting

#!/bin/sh

	echo "1. Area of Circle"
	echo "2. Area of Rectangle"
	echo "3. Area of Square"
	echo "4. Area of Triangle"
	echo "5. Factorial"
	echo "6. Compare"
        echo "7. Exit"
	echo "enter the choice of operation -->"
	read c
	case $c in
1) 
	echo -n "Enter radius of circle -->"
	read r
	echo -n "Area of circle is --> $carea"
	carea= echo "3.14*$r*$r"|bc
;;
2)
	echo -n "Enter Length of Rectangle -->"
	read l
	echo -n "Enter Breadth of Rectangle -->"
	read b
	rarea=`expr $l \* $b`
	echo "Area of Rectangle is --> $rarea"
;;
3)
	echo -n "Enter Length of Square -->"
	read l
	sarea=`expr $l \* $l`
	echo "Area of Square is --> $sarea"
;;
4)
	echo -n "Please enter the base and height of the triangle --> "
	read base 
	read height
	area=`expr "scale=2; 1/2*$base*$height" |bc`
	echo "area of the triangle = $area"
;;
5)
	echo "Total no of factorial wants"
	read fact
	
	ans=1
	counter=0
	while [ $fact -ne $counter ]
do
        counter=`expr $counter + 1`
        ans=`expr $ans \* $counter`
done
	echo "Total of factorial is $ans"
;;
6)
	echo "Compare Numbers"
	echo ""
	echo "Enter a first value"
	read FIRST
	echo ""
	echo "Enter a second number"
	read SECOND
	echo ""
	if [ $FIRST = $SECOND ]
	then
		OUTPUT="Both values are equal"
	else
		if [ $FIRST -gt $SECOND ]
		then
			OUTPUT="$FIRST is greater"
		else
			OUTPUT="$SECOND if greater"
	fi
		fi
		echo $OUTPUT
		echo ""

;;
*)
echo "wrong input"
;;
esac