OCP-3.swift

protocol GeometricFigure {
    func area() -> Double
}

class Circle: GeometricFigure  {
    var radius: Double
    
    init(radius: Double) {
        self.radius = radius
    }
    
    func area() -> Double {
        return Double.pi * radius * radius
    }
}

class Rectangle: GeometricFigure {
    var width: Double
    var height: Double
    
    init(width: Double, height: Double) {
        self.width = width
        self.height = height
    }
    
    func area() -> Double {
        return width * height
    }
}

class AreaCalculator {
    func area(figure: GeometricFigure) -> Double {
        return figure.area()
    }
}