Pattern matching

Let you pattern match across various variants of an enum and run some logic

// Define an enum called Shape
enum Shape {
    Circle(f64),  // Variant with associated data (radius)
    Square(f64),  // Variant with associated data (side length)
    Rectangle(f64, f64),  // Variant with associated data (width, height)
}

// Function to calculate area based on the shape
fn calculate_area(shape: Shape) -> f64 {
    match shape {
        Shape::Circle(radius) => std::f64::consts::PI * radius * radius,
        Shape::Square(side_length) => side_length * side_length,
        Shape::Rectangle(width, height) => width * height,
    }
}

fn main() {
    // Create instances of different shapes
    let circle = Shape::Circle(5.0);
    let square = Shape::Square(4.0);
    let rectangle = Shape::Rectangle(3.0, 6.0);

    // Calculate and print the areas
    println!("Area of circle: {}", calculate_area(circle));
    println!("Area of square: {}", calculate_area(square));
    println!("Area of rectangle: {}", calculate_area(rectangle));
}