example2_protected_members_constructor_inheritance.cpp

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
#include <iostream>
#include <string>

class Shape {
protected:
    double area;

public:
    Shape() : area(0) {}

    virtual void calculateArea() = 0;

    void displayArea() const {
        std::cout << "Area: " << area << std::endl;
    }
};

class Circle : public Shape {
private:
    double radius;

public:
    Circle(double r) : radius(r) {}

    void calculateArea() override {
        area = 3.14159 * radius * radius;
    }
};

class Rectangle : public Shape {
private:
    double length, width;

public:
    Rectangle(double l, double w) : length(l), width(w) {}

    void calculateArea() override {
        area = length * width;
    }
};

int main() {
    Circle circle(5);
    Rectangle rectangle(4, 6);

    circle.calculateArea();
    rectangle.calculateArea();

    std::cout << "Circle ";
    circle.displayArea();

    std::cout << "Rectangle ";
    rectangle.displayArea();

    return 0;
}