Area & Circumference of Circle

Algorithm
Step 1 : Start
Step 2 : Define constant pi = 3.14
Step 3 : Read the value of radius
Step 4 : Calculate area using formulae: pi × radius2
Step 5 : Calculate circumference using formulae: 2 × pi × radius
Step 6 : Print area and circumference
Step 7 : Stop

Program (circle.sh)
# Circle metrics using readonly variable
pi=`expr "scale=2; 22 / 7" | bc`
readonly pi # pi value cannot be altered
echo -n "Enter value for radius : "
read radius
area=`expr "scale=2; $pi * $radius * $radius" | bc`
circum=`expr "scale=2; 2 * $pi * $radius" | bc`
echo "Area : $area"
echo "Circumference : $circum"



Output
[vijai@localhost simple]$ sh circle.sh
Enter value for radius : 12
Area : 452.16
Circumference : 75.36