Lesson 3: Create the cone class

The cone class implements the getColor and setColor methods that the base shape class defines.

1. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Field.
2. In the Create C++ Field window, in the Name field, type color.
3. In the Type list, type string and click Finish.
4. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
5. In the Create C++ Method window, in the Name field, type getColor.
6. In the Return type list, type string and click Finish.
7. In the cone class, double-click the getColor method and, in the code editor, specify the body of the getColor method as follows:{return color;};
8. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
9. In the Create C++ Method window, in the Name field, type setColor and click Finish.
10. In the cone class, double-click the setColor method, and in the code editor, specify the signature of the method as: void setColor(string c) and the body of the setColor method as {color = c;};

The cone class implements the getSize and setSize methods that the base shape class defines. The size field stores the height of the cone.

1. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Field.
2. In the Create C++ Field window, in the Name field, type size.
3. From the Type list, select double and click Finish.
4. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
5. In the Create C++ Method window, in the Name field, type getSize.
6. In the Return type list, click the down arrow beside void, select double, and click Finish.
7. In the cone class, double-click the getSize method and, in the code editor, specify the body of the getSize method as follows: {return size;};
8. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
9. In the Create C++ Method window, in the Name field, type setSize and click Finish.
10. In the cone class, double-click the setSize method and, in the code editor, specify the body of the setSize method as follows: {size = s < 0 ? 0:S;};

The cone class implements the getRadius and setRadius methods that the base shape class defines. The radius field stores the radius of the base of the cone. The application uses the radius to calculate the circumference and the volume of the cone.

1. In the diagram editor, right-click the cone class; then click Add C/C++ > Field.
2. In the Create C++ Field window, in the Name field, type radius.
3. In the Type list, click double, and click Finish.
4. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
5. In the Create C++ Method window, in the Name field, type getRadius.
6. From the Return type list, select double and click Finish.
7. In the cone class, double-click the getRadius method and, in the code editor, specify the body of the getRadius method as follows: {return radius;};
8. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
9. In the Create C++ Method window, in the Name field, type setRadius and click Finish.
10. In the cone class, double-click the setRadius method and, in the code editor, specify the body of the setRadius method as follows:{radius = r < 0 ? 0:r;};

The cone class implements the surface area and volume methods that the shapes3d class defines. The formula that calculates the surface area of a cone is πr² (r + (r2 + h2)1/2). The formula that calculates the volume of a cone is 1/3 x πr²h.

1. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
2. In the Create C++ Method window, in the Name field, type surfaceArea.
3. From the Return type list, select double and click Finish.
4. In the cone class, double-click the surfaceArea method and, in the code editor, specify the body of the surfaceArea method as follows:{return pi * radius * (radius + (pow(pow(radius,2) + pow(size,2),0.5)));};
5. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
6. In the Create C++ Method window, in the Name field, type volume and click Finish.
7. In the cone class, double-click the volume method and, in the code editor, specify the body of the volume method as follows: {return 0.333 * pi * (pow(radius,2) * size);};

The cone class implements the set and print methods that the base shape class defines.

1. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
2. In the Create C++ Method window, in the Name field, type print and click Finish.
3. In the cone class, double-click the print method and, in the code editor, specify the body of the print method as follows:

   { cout  << "Cone:"
   			<< "\n\tLength = " << getSize()
   			<< "\n\tArea   = " << surfaceArea()
   			<< "\n\tVolume = " << volume()
   			<< "\n\tColor  = " << getColor()
   			<< "\n\n";
   };

4. In the diagram editor, in the classdiagram.dnx diagram, right-click the cone class; then click Add C/C++ > Method.
5. In the Create C++ Method window, in the Name field, type set and click Finish.

The cone.cpp class file contains the implementation of the set method, as well as the constructor and destructor. You modify the body of the set method to prompt the user to specify the size and radius of the cone. You must also edit the default constructor to set the initial values of the new cone class.

1. In the C++ Project Explorer view, double-click the cone.cpp class.
2. In the code editor, in the cone.cpp class, specify the body of the default constructor as follows: {color="Transparent"; radius=0; size=0;}
3. In the method declaration section, specify the body of the set method as follows:

   void cone::set()	{
   	double size;
   	double radius;
   	string color;
   	
   	cout << "Enter the height of the cone: ";
   	cin >> size; 
   	setSize(size);
   	
   	cout << "Enter the radius of the base of the cone: ";
   	cin >> radius; 
   	setRadius(radius);
   	
   	cout << "Enter the color of the cone: ";
   	cin >> color;
   	setColor(color);
   }

4. To save the project, click File > Save.

Before you can run the application, you must add the include statement to the main.cpp class to include the new cone class. You can run the application and instantiate the new cone class by modifying the main.cpp class.

1. In the C++ Project Explorer view, double-click the main.cpp class.
2. In the declaration section of the class, below #include "tetrahedron.h", add the following include statement: #include "cone.h"
3. In the code editor, in the main body of the class, add the following code:

   //instantiate and run the cone class 
   		cone c;
   		c.print();
   		c.set();
   		c.print();

4. To save and build the project, click File > Save.
5. Click Run.