COS3711 Assigment 2 Year Module Due 2026

UNIVERSITY OF SOUTH AFRICA
College of Science, Engineering and Technology


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COS3711: Advanced Programming

Assignment 2 — 2026

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COS3711
Module Code:
Advanced Programming
Module Name:
Assignment 2
Assignment:
2026
Year:




Submitted in partial fulfilment of the require-
ments for Advanced Programming — UNISA 2026

,UNISA | COS3711 Advanced Programming – Assignment 2



Question 1: Inheritance Hierarchy and Shape Drawing Application

Object-oriented design makes drawing applications considerably cleaner when shapes share
common properties. The Qt framework is well suited for this kind of work because its QPainter
API maps naturally onto pen-and-brush abstractions, and its widget system handles the ren-
dering surface (Stroustrup, 2013). The class hierarchy specified in the assignment separates
shared state from shape-specific measurements, which is exactly what abstract base classes
are for.


1.1 Design Overview


The hierarchy has three abstract layers and four concrete leaf classes. Shape holds pen width,
pen colour, and fill colour. Shape1Property extends Shape with one integer property (used
as radius for circles or side-length for squares). Shape2Property extends Shape1Property
with a second integer property (used for the second dimension of rectangles and ellipses).
The four concrete classes, Circle, Square, Ellipse, and Rectangle, each implement the pure
virtual draw() function. The UML diagram below captures this structure.

Shape
penWidth, penColour, fillColour
draw()




Shape1Property
property1
draw()




Shape2Property
property2
draw()




Circle Square
draw() draw()




Ellipse Rectangle
draw() draw()



Figure 1: UML inheritance hierarchy for the Shapes application



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, UNISA | COS3711 Advanced Programming – Assignment 2



1.2 Header Files


shape.h

1 # ifndef SHAPE_H
2 # define SHAPE_H
3


4 # include < QColor >
5 # include < QPainter >
6


7 class Shape {
8 public :
9 Shape () ;
10 Shape ( int penWidth , QColor penColour , QColor fillColour ) ;
11 virtual ~ Shape () {}
12


13 // Getters
14 int getPenWidth () const ;
15 QColor getPenColour () const ;
16 QColor getFillColour () const ;
17

18 // Setters
19 void setPenWidth ( int pw ) ;
20 void setPenColour ( QColor pc ) ;
21 void setFillColour ( QColor fc ) ;
22


23 virtual void draw ( QPainter & painter ) = 0;
24


25 protected :
26 int m_penWidth ;
27 QColor m_penColour ;
28 QColor m_fillColour ;
29 };
30


31 # endif // SHAPE_H




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