Java Program to Calculate and Display Area of a Circle

Given a radius of the circle, write a java program to calculate and display the area of the circle. (Take ∏=3.142)

Example

Input : radius= 5
Output: Area of circle is : 78.55

Input : radius= 8
Output: Area of circle is : 201.08

As we know to calculate the area of a circle, the radius of the circle must be known, so if the radius of the circle is known, then the area of the circle can be calculated by using the formula:

Area = 3.142*(radius)*(radius)

Below is the Java Program to calculate the area of the circle:- 

Java

// Java program to calculate the area of the
public class GFG {
    public static void main(String[] args)
    {
        int radius;
        double pi = 3.142, area;
        radius = 5;
        // calculating the area of the circle
        area = pi * radius * radius;
        // printing the area of the circle
        System.out.println("Area of circle is :" + area);
    }
}

Output

Area of circle is :78.55

Time complexity: O(1) since performing constant operations

Auxiliary Space: O(1)