Introduction:

In this article, we will explore different methods to compute the area of a circle, providing step-by-step explanations and sample code for each method. Whether you are a beginner or an experienced programmer, this blog post will guide you through various approaches to solving this mathematical problem efficiently.

Method 1: Using the Math Library

The Math library in C# provides a built-in method, Math.PI, which returns the value of pi (π). We can utilize this constant to calculate the area of a circle by multiplying π with the square of the circle's radius. The formula for the area of a circle is A = π * r^2, where A represents the area and r is the radius.

using System;

class Program
{
    static void Main()
    {
        double radius = 5.0;
        double area = Math.PI * Math.Pow(radius, 2);
        
        Console.WriteLine("The area of the circle is: " + area);
    }
}

Output:

The area of the circle is: 78.53981633974483

Method 2: User-Input Radius

 In this method, we enhance the previous code by allowing the user to input the radius of the circle. We prompt the user to enter a value, convert it to a double, and use the entered radius to calculate the area.

using System;

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter the radius of the circle:");
        string input = Console.ReadLine();
        double radius = Convert.ToDouble(input);
        
        double area = Math.PI * Math.Pow(radius, 2);
        
        Console.WriteLine("The area of the circle is: " + area);
    }
}

Output:

Enter the radius of the circle:
10
The area of the circle is: 314.1592653589793

Method 3: Object-Oriented Approach

 In this method, we create a Circle class to encapsulate the concept of a circle. The class includes a method to calculate the area of the circle based on the provided radius. This approach promotes code reusability and follows the principles of object-oriented programming.

using System;

class Circle
{
    public double Radius { get; set; }
    
    public double CalculateArea()
    {
        return Math.PI * Math.Pow(Radius, 2);
    }
}

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter the radius of the circle:");
        string input = Console.ReadLine();
        double radius = Convert.ToDouble(input);
        
        Circle circle = new Circle { Radius = radius };
        double area = circle.CalculateArea();
        
        Console.WriteLine("The area of the circle is: " + area);
    }
}

Output:

Enter the radius of the circle:
7.5
The area of the circle is: 176.71458676442586

Conclusion:

In this blog post, we explored various methods to calculate the area of a circle using C#. We started with the simplest approach using the Math library, then extended it to include user input, and finally demonstrated an object-oriented approach. By following the code examples and explanations provided, you should now have a solid understanding of how to compute the area of a circle in C#.