Question

Write Java code that takes input from the user for the radius (double) of a circle, and create a circle with that radius. The program should then print a sentence with the circumference and area of the circle. You should use the appropriate Circle methods to obtain the circumference and area of the circle rather than calculating these values yourself.

Sample run:

Enter the radius of the circle:
> 3
A circle with a radius 3.0 has a circumference of 18.84955592153876 and an area of 28.274333882308138
Hint: You can approach this problem by saving the double (radius) as a variable and then creating the Circle, or you can create the Circle and use methods from the Circle class to set the radius.

Answer 1

To create a Java program that takes input for the radius of a circle, creates a circle object, and prints its circumference and area, you can use the Scanner class to get user input and the Circle class to calculate the circumference and area

Step-by-step explanation:

To write Java code that takes input from the user for the radius of a circle and creates a circle with that radius, you can use the Scanner class to get user input and then create an instance of the Circle class with the provided radius. Here's an example:

import java.util.Scanner;

public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the radius of the circle: ");
double radius = scanner.nextDouble();

Circle circle = new Circle(radius);

double circumference = circle.getCircumference();
double area = circle.getArea();

System.out.println("A circle with a radius " + radius + " has a circumference of " + circumference + " and an area of " + area);
}
}

The Java program prompts the user for the radius of a circle, creates a Circle object with that radius, and prints the circumference and area using the Circle's methods. The formula used for calculation is 2πr for circumference and πr² for area.

To calculate the circumference and area of a circle in Java, we can create a program that uses the user's input for the circle's radius. We will utilize the formula 2πr for the circumference and πr² for the area, where r represents the radius. Here is a sample Java code that achieves this:

import java.util.Scanner;

class Circle {
private double radius;

public Circle(double r) {
radius = r;
}

public double getCircumference() {
return 2 * Math.PI * radius;
}

public double getArea() {
return Math.PI * Math.pow(radius, 2);
}
}

public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the radius of the circle: ");
double radius = scanner.nextDouble();
Circle circle = new Circle(radius);
System.out.println("A circle with a radius " + radius + " has a circumference of " + circle.getCircumference() + " and an area of " + circle.getArea());
scanner.close();
}
}

When running the program, the user will be prompted to enter the radius, after which the code will create a Circle object and print out the circle's circumference and area using the object's methods.