Basic Java program to find area and perimeter of circle

1.Write a Basic java example  program to find area of circle

•  To calculate the area of circle we need to ask user to enter radius of the circle so that we can calculate area of circle using formula area of circle =PI* radius * radius

1. package com.BasicJavaProgramsExamples;
2. import java.util.Scanner;
3. public Class AreaOfCirle{ 
5.  
6. public static void main(String args[]) {
7.  
8. int radius = 0;
9. Scanner in= new Scanner(System.in);
10. System.out.println("Please enter radius of a circle");
11.  
12.     radius=in.nextInt();
13.      
14. /*
15.  * where r is a radius of a circle then Area of a circle is
16.  *Area= pi * r * r
17.  *
18.  */
19.          
20.     double area=Math.PI* radius * radius;
21.       
22.     System.out.println("Area of the circle ="+area);
23.  
24. }
25. }

Output:

1. Please enter radius of a circle
2. 23
3. Area of the circle =1661.9025137490005

2.Write a Basic java example program to find perimeter of circle

•  To calculate the perimeter  of circle we need to ask user to enter radius of the circle so that we can calculate perimeter  of circle using formula area of circle =2* PI* radius

  

1. package com.BasicJavaProgramsExamples;
2. import java.util.Scanner;
3. public Class PerimeterOfCirle{ 
5.  
6. public static void main(String args[]) {
7.  
8. int radius = 0;
9. Scanner in= new Scanner(System.in);
10. System.out.println("Please enter radius of a circle");
11.  
12.     radius=in.nextInt();
13.      
14. /*
15.  * where r is a radius of a circle then perimeter of a circle is
16.  *Area= pi * r * r
17.  *
18.  */
19.          
20.     double perimeter =2* Math.PI* radius;
21.  
22.     System.out.println("Perimeter of the circle ="+perimeter );
23.  
24. }
25. }

Output:

1. Please enter radius of a circle
2. 12
3. Perimeter of the circle =75.39822368615503