01: #include <iostream>
03: using namespace std;
05: /**
06:    A class that describes triangle shapes like this:
07:    []
08:    [][]
09:    [][][]
10:    . . .
11: */   
12: class Triangle {
14: public:
15:    Triangle(int w);
16:    int get_area() const;
17: private:
18:    int width;  
19: };
21: /**
22:    Constructs a triangle with a given width.
23:    @param w the width of the triangle base
24: */
25: Triangle::Triangle(int w)
26: {  width = w;  }
30: /**
31:    Computes the area of the triangle shape.
32:    @return the area
33: */
34: int Triangle::get_area() const
35: {  if (width == 1) return 1;
37:    Triangle smaller_triangle(width - 1);
38:    int smaller_area = smaller_triangle.get_area();
39:    return smaller_area + width;
40: }
41: 
42: int main()
43: {  Triangle t(4);
45:    cout << "Area: " << t.get_area() << endl;
46:    return 0;
47: }