Java Program to calculate area of circle - 5 different ways

Java Program to calculate area of circle – 5 different ways

The java program to calculate area of circle has been written in five different ways such as Scanner class, direct value initialization, Buffered Reader class, Command Line argument, and using Constructor. Java Program to calculate area of circle – 5 different ways are as follows:

1. Java program to Calculate Area of circle using Scanner class:

Program:

import java.io.*;
import java.util.*;
class CircleArea
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.println("Enter radius of circle");
int r= sc.nextInt();
double pi=3.14;
double Area;
Area =pi*r*r;
System.out.println("The area of circle is "+Area);
}
}

Output:

Enter radius of circle 5
The area of circle is 78.5

2. Java program to calculate area of Circle using direct value initialization:

Program:

import java.io.*;
class CircleArea
{
public static void main(String args[])
{
int r=5;
double pi=3.14;
double Area;
Area =pi*r*r;
System.out.println("The area of circle is "+Area);
}
}

Output:

The area of circle is 78.5

3. Java Program to calculate Area of Circle using Buffered Reader Class:

program:

import java.util.*;
import java.lang.*;
import java.io.*;
class CrArea
{
public static void main(String args[]) throws Exception
{
double pi=3.14, area;
BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the radius");
int r= Integer.parseInt(br.readLine());
area=pi*r*r;
System.out.println("The area of circle is "+area);
}
}

output:

Enter the radius
10
The area of circle is 314.0

4. Java program to calculate Area of Circle using Command Line Arguments:

Program:

import java.util.*;
class AreaOfCircle
{
public static void main(String args[])
{
double area, pi=3.14;
int r= Integer.parseInt(args[0]);
System.out.println(r);
area=pi*r*r;
System.out.println("The area of circle is "+area);
}
}

Compile:

javac AreaOfCircle.java

Run:

java AreaOfCircle 10
The Area of circle is 314.0

5. Java Program to calculate Area of Circle Using Constructor:

Program:

import java.util.*;
class AreaCircle
{
	double area;
	AreaCircle(double r)
	{
	 area= 3.14*r*r;
 
	}
}
class CrArea
{
   public static void main(String args[]) 
    {   
      Scanner sc= new Scanner(System.in);
      System.out.println("Enter the radius of circle");
      double radius= sc.nextDouble();      
      AreaCircle obj =new AreaCircle(radius);
	  System.out.println("Area of Circle is " + obj.area);      
   }
 }

Output:

Enter the radius of circle
10
Area of Circle is 314.0

Java Program to calculate Circumference of circle – 5 different ways

The java program to calculate circumference of circle has been written in five different ways such as Scanner class, direct value initialization, Buffered Reader class, Command Line argument, and using Constructor. Java Program to calculate Circumference of circle – 5 different ways are as follows:

1. Java program to Calculate Circumference of circle using Scanner class:

Program:

import java.io.*;
import java.util.*;
class Circumference
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.println("Enter radius of circle");
int r= sc.nextInt();
double pi=3.14;
double circum;
circum =2*pi*r;
System.out.println("The circumference of circle is "+circum);
}
}

output:

Enter radius of circle
5
The circumference of circle is 31.4

2. Java program to Calculate Circumference of circle using Direct Value initialization:

Program:

import java.io.*;
class Circumference
{
public static void main(String args[])
{
int r=5;
double pi=3.14;
double circum;
circum =2*pi*r;
System.out.println("The circumference of circle is "+circum);
}
}

Output:

The circumference of circle is 31.4

3.Java Program to calculate Circumference of Circle using Buffered Reader class:

program:

import java.util.*;
import java.lang.*;
import java.io.*;
class Circumference
{
public static void main(String args[]) throws Exception
{
double pi=3.14,circum;
BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter the radius");
int r= Integer.parseInt(br.readLine());
circum=2*pi*r;
System.out.println("The circumference of circle is "+circum);
}
}

Output:

Enter the radius
5
The circumference of circle is 31.4

4. Java Program to calculate Circumference of Circle Using Command Line Argument:

Program:

import java.util.*;
class Circumference
{
public static void main(String args[])
{
double circum, pi=3.14;
int r= Integer.parseInt(args[0]);
System.out.println(r);
circum=2*pi*r;
System.out.println("The Circumference of circle is "+circum);
}
}

Compile:

javac Circumference.java

Run:

java Circumference
5
The Circumference of circle is 31.4

5. Java Program to calculate Circumference of Circle using Constructor:

Program:

import java.util.*;
class Circumference
{
	double circum;
	Circumference(double r)
	{
	 circum= 2*3.14*r;
 
	}
}
class CrArea
{
   public static void main(String args[]) 
    {   
      Scanner sc= new Scanner(System.in);
      System.out.println("Enter the radius of circle");
      double radius= sc.nextDouble();      
      Circumference obj =new Circumference(radius);
	  System.out.println("Circumference of Circle is " + obj.circum);      
   }
 }

Output:

Enter the radius of Circle 
5
Circumference of Circle is 31.4