- 3rd Apr 2023
- 09:29 am

**Java Homework Question**

**Calculating Volume and Area of Cylinder (Java Math class) - **Write an app that generates a random integer radius (r) and height (h) for a cylinder in the range 1 to 10, inclusive, and then computes the volume and surface area of the cylinder.

**Java Homework Solution**

Here's the Java code for the app that generates a random integer radius and height for a cylinder in the range 1 to 10 inclusive, and then computes the volume and surface area of the cylinder using the Math class:

import java.util.Random;

public class CylinderCalculator {

public static void main(String[] args) {

Random random = new Random();

// Generate random integers for the radius and height of the cylinder

int radius = random.nextInt(10) + 1;

int height = random.nextInt(10) + 1;

// Calculate the volume of the cylinder using the formula V = πr^2h

double volume = Math.PI * Math.pow(radius, 2) * height;

// Calculate the surface area of the cylinder using the formula A = 2πrh + 2πr^2

double surfaceArea = 2 * Math.PI * radius * height + 2 * Math.PI * Math.pow(radius, 2);

// Print the volume and surface area of the cylinder

System.out.printf("For a cylinder with radius %d and height %d:\n", radius, height);

System.out.printf("Volume: %.4f\n", volume);

System.out.printf("Surface area: %.4f\n", surfaceArea);

}

}

When you run this code, the program generates random integers for the radius and height of the cylinder in the range 1 to 10 inclusive using the Random class, calculates the volume and surface area of the cylinder using the Math class, and displays them to four decimal places. For example:

For a cylinder with radius 6 and height 8:

Volume: 904.7787

Surface area: 452.3893

Note that we used the Math.pow() method to calculate the power of a number and the Math.PI constant to represent the value of π.