Question

Polymorphism and Inheritance

Shape.h

class Shape {

            string color;

            bool filled;

public:

            Shape();

            Shape(string, bool);

            string getColor();

            bool isFilled();

            void setColor(string);

            void setFilled(bool);

            string toString();

//virtual string toString();

};

Rectangle.h

class Rectangle : public Shape {

            double length;

            double width;

public:

            Rectangle();

            Rectangle(double, double);

            Rectangle(double, double, string, bool);

            double getLength();

            double getWidth();

            void setLength(double);

            void setWidth(double);

            double getArea();

            double getPerimeter();

printShape() function prototypes:

void printShape(Shape); or

void printShape(Shape &);

^^test which works correctly

Make a Rectangle class and a Triangle class that extend Shape class

^^not sure how to do this

the main that has to be used

int main() {

Shape s;

Rectangle r(5,6, "red", true);

Triangle t(6, 10, "blue", true);

printShape(s);

Shape s1("blue", false);

printShape(s1);

//add virtual and pass the object by reference

printShape(r);

printShape(t);

return 0;

}

the instances need to be created and printShape() method needs to be called

triangle formula used is =1/2base*height

Answer 1

The C++ code for the above problem statement is as follows:-

#include <iostream>
using namespace std;
class shape
{
public:
string color;
bool filled;
shape()
{
color="";
filled=false;
}
shape(string c,bool f)
{
color=c;
filled=f;
}
string getColor()
{
return color;
}
bool isFilled()
{
return filled;
}
void setColor(string c)
{
color=c;
}
void setFilled(bool f)
{
filled=f;
}
void toString() //virtual method of toString() as mentioned in the question.
{
string f,s;
if(filled==true)
f="filled";
else
f="not filled";
cout<<"\n Color of shape is: "<<color<<" and the shape is: "<<f;
}
virtual void printShape(shape S) //virtual method and pass object by reference
{
string f,s;
if(S.filled==true)
f="filled";
else
f="not filled";
cout<<"\n Color of shape is: "<<S.color<<" and the shape is: "<<f;
}
};
class rectangle : public shape //class rectangle inherit class shape
{
double length;
double width;
public:
rectangle()
{
length=0;
width=0;
filled=false;
color="";
}
rectangle(double l,double w)
{
length=l;
width=w;
}
rectangle(double l,double w,string s,bool f)
{
length=l;
width=w;
filled=f;
color=s;
}
double getLength()
{
return length;
}
double getWidth()
{
return width;
}
void setLength(double l)
{
length=l;
}
void setWidth(double w)
{
width=w;
}
double getArea()
{
return length*width;
}
double getPArimeter()
{
return 2*(length+width);
}

string toString() //calling the parent class method
{
shape::toString();
}
void printShape(rectangle R) //virtual method and pass object by reference
{
string f;
if(R.filled==true)
f="filled";
else
f="not filled";
cout<<"\n Color of rectangle is: "<<R.color<<" and the rectangle is: "<<f;
}
};
class triangle : public shape //class rectangle inherit class shape
{
double base;
double height;
public:
triangle()
{
height=0;
base=0;
filled=false;
color="";
}
triangle(double h,double b)
{
height=h;
base=b;
}
triangle(double h,double b,string s,bool f)
{
height=h;
base=b;
filled=f;
color=s;
}
double getHeight()
{
return height;
}
double getBase()
{
return base;
}
void setHeight(double h)
{
height=h;
}
void setBase(double b)
{
base=b;
}
double getArea()
{
return 0.5*height*base;
}
string toString() //calling the parent class method
{
shape::toString();
}
void printShape(triangle T) //virtual method and pass object by reference
{
string f;
if(T.filled==true)
f="filled";
else
f="not filled";
cout<<"\n Color of triangle is: "<<T.color<<" and the triangle is: "<<f;
}
};
int main()
{
shape s;
shape s1("blue",false);
shape *sh; //declaring pointer of shape class
sh=&s; // storing the address of the shape s object
sh->printShape(s); //for calling method printShape() for shape s
sh=&s1;
sh->printShape(s1); //for calling method printShape() for shape s1
rectangle r(5,6,"Red",true);
rectangle *rec;
rec=&r; //for calling method printShape() for rectangle r
rec->printShape(r);
triangle t(6,10,"blue",true);
triangle *tri;
tri=&t; //for calling method printShape() for triangle t
tri->printShape(t);
   return 0;
}

The documentation is done by the single line comment where ever necessary, the output of the above code is as follows:-

Color of shape is: and the shape is: not filled
Color of shape is: blue and the shape is: not filled
Color of rectangle is: Red and the rectangle is: filled
Color of triangle is: blue and the triangle is: filled