Write a program to calculate area and perimeter of a circle

The given example will teach you the method for preparing a program to
calculate the area and perimeter of a circle. First of all name a class as
"CircleArea" under Java I/O package and define and integer r=o, which
is the radius of the circle. Now use try exception to handle errors and
other exceptional events. As we have to input the value of radius here create a
buffered class with an object as 'br1'. This create a buffering character input
stream that uses a default sized input buffer. The InputStreamReader here works
as a translator that converts byte stream to character stream. Now type message
that "Enter radius of circle" in the System.out.println method.
Now use the parseInt() method of the Integer class in order to convert from
external numeric format to internal format. Now create the Math class in which
all the mathematical functions are defined. This Math class can be imported from
the java.lang.* package. Write the program for both
the cases: radius and perimeter.
Before ending the program use the Catch mechanism that detects and
catch user input errors. In the end compile and run the program and enter your
desired value as radius for calculating the radius and perimeter of the
circle.
Here is the code of the program:
import java.io.*;
class CircleArea{
public static void main(String[] args){
int r=0;
try{
BufferedReader br1 = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter Radius of Circle : ");
r = Integer.parseInt(br1.readLine());
double area = java.lang.Math.PI*r*r;
System.out.println("Area of Circle : "+area);
double perimeter =2*java.lang.Math.PI*r ;
System.out.println("Perimeter of Circle : "+perimeter);
}
catch(Exception e){
System.out.println("Error : "+e);
}
}
}
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Current Comments
3 comments so far (post your own) View All Comments Latest 10 Comments:Very nice, I told my son about this, and now it's helped him alot. Thank-you.
Posted by Michael Hickenbottom on Monday, 01.28.08 @ 01:38am | #46334
can u tell what is use of writig String[] args in main method
Posted by abhas on Sunday, 05.13.07 @ 09:21am | #15768
it is easy to understand & write .
Posted by sumesh on Wednesday, 05.2.07 @ 11:43am | #15152