Question

C++

Could you check my code, it work but professor said that there are some mistakes(check virtual functions, prin() and others, according assignment) .

Assignment:

1. Define an abstract base class called BasicShape. The BasicShape class should has the following members: (Reference: Fig 12.9 and 12.10) a) Protected Member Variable: area (a double used to hold the shape's area) b) Private Member Variable: name (a string to indicate the shape's type) c) Constructor and Public Member Functions BasicShape double a, string n): A constructor that sets value of member area with a and member name with 1n calcAreal: This public function should be a pure virtual function. print0: A pubic virtual function that prints the value of data member area getName):A pubic function that returns the value of data member name 2. Define a class named Circle. It should be derived from the BasicShape class It should have the following members: (Reference: Fig 12.11 and 12.12) a) Private Member Variable: radius (a double used to hold the circle's radius) b) Constructor and Public Member Functions Circleldouble a, string n, double r): constructor that should call the base class constructor to set value of member area with a and name with n. The constructor will also set value of member radius with γ caledread: Overridden function that calculates the area of the circle (area = 3.14159 * radius * radius) and stores the result in the inherited member area. · print0: Overridden function that will print the radius, inherited member area and inherited member name. This function should use the base class's print function to print the area. 3. After you have created these classes, create a test program (Reference: Fig 12.17) Write a function named poly whose only parameter is a BasicShape pointer Function poly should use the BasicShape pointer to invoke calcArea function and print function. » In main0: define a Circle object with radius 10, name Round and area initialized to 0 Frommain), call the function poly such that it will polymorphically invoke calcArea function and print function of the Circle object.

My code:

#include<iostream>
#include<string>
using namespace std;

class BasicShape { //Abstract base class

protected:

double area;

private:
   string name;

public:

BasicShape(double a, string n) {
area=a;
name=n;
}

void virtual calcArea()=0;//Pure Virtual Function

virtual void print() {

cout<<"Area of "<<getName()<<" is: "<<area<<"\n";

}
string getName(){
   return name;
}
};

class Circle : public BasicShape {

private:

double radius;

public:

Circle(double a, string n, double r): BasicShape(a,n) {

radius=r;

}

void calcArea() {

area = 3.14159*radius*radius; //use include math for pi and pow

}

void print() {

cout<<"Radius is: "<<radius<<" and area is "<<BasicShape::print()<<"of "<<getName()<<"\n";
}

};

void poly(BasicShape *bs) {

bs->calcArea();

bs->print();

}

int main() {

Circle c(0,"Round", 10);
poly(&c);
cout<<"\n\n";
return 0;

}

Answer 1

#include <iostream>
using namespace std;
class BasicShape
{
//a) Protected Member Variable: area (a double used to hold the shape’s area).
protected:
double area;
//b) Private Member Variable: name (a string to indicate the shape’s type)
private:
string name;
public:
//BasicShape(double a, string n): A constructor that sets value of member area with a and member name with n.
BasicShape(double a, string n)
{
area = a;
name = n;
}
//calcArea(): This public function should be a pure virtual function.
virtual void calcArea() = 0;
//print(): A public virtual function that only prints the value of data member area.
virtual void print()
{
cout<<"Area: "<<area<<endl;
}
//getName():A public function that returns the value of data member name.
string getName()
{
return name;
}
};