Question

This is in C++. It is a program demonstrating how a class can be used to modify a box in different ways/throw invalid arguments. I am having trouble understanding the code as the teacher did not include comments, can someone please add some detailed ones to help?

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

class Box
{

double height, width, depth;

public:
   

Box()
{
height = width = depth = 1.0;
}


Box(double h, double w, double d)
{
height = h;
width = w;
depth = d;
}

void resize(double h, double w, double d)
{
height = h;
width = w;
depth = d;
}

void set_height(double h)
{
height = h;

if(h < 0.01)
{

throw invalid_argument("Height is less than 0.01.");
}
}

void set_width(double w)
{
width = w;

if(w < 0.01)
{

throw invalid_argument("Width is less than 0.01.");
}
}

void set_depth(double d)
{
depth = d;

if(d < 0.01)
{

throw invalid_argument("Depth is less than 0.01.");
}
}

double get_height()
{
return height;
}

double get_width()
{
return width;
}

double get_depth()
{
return depth;
}

double volume()
{

return height * width * depth;
}

void to_string()
{

cout << "Height:\t" << height << endl;
cout << "Width :\t" << width << endl;
cout << "Depth :\t" << depth << endl;

cout << endl;
}
};

int main()
{

Box b1, b2(9, 8, 3);

cout << "Box b1:" << endl;
b1.to_string();

cout << "Box b2:" << endl;
b2.to_string();

cout << "Volume of b1: " << b1.volume() << endl;
cout << "Volume of b2: " << b2.volume() << endl;
cout << endl;

cout << "Changing width of b2 to 0.3" << endl;
b2.set_width(0.90);

cout << "Changing width of b2 to 0.90, width: " << b2.get_width() << endl;
cout << "Volume: " << b2.volume() << endl;
cout << endl;

  
b1.resize(2.3, 1.5, 5.2);

cout << "After resizing b1:" << endl;
b1.to_string();

cout << "New volume:" << endl;
cout << "Volume: " << b1.volume() << endl;


try
{
    cout << "If width is set under 0.01:" << endl;
b1.set_width(0.001);
}

catch(invalid_argument e)
{
cout << "0.01 is the minimum width for the box!" << endl;
}

return 0;
}

Answer 1

#include<iostream>
#include<stdexcept>
using namespace std;
//a class Box consisting of data members height,width and depth declared as private which can't be accesible outside class
class Box
{
double height, width, depth;
public:

//default constructor which initializes width,height & depth to 1.0
Box()
{
height = width = depth = 1.0;
}

//parameterized constructor used for initializing data members of class
Box(double h, double w, double d)
{
height = h;
width = w;
depth = d;
}
//increasing dimensions for the box by using resize function and storing it in height,width & depth
void resize(double h, double w, double d)
{
height = h;
width = w;
depth = d;
}
//used for initializing height value
void set_height(double h)
{
height = h;
//checks height value and if it is less than 0.01 then an invalid_argument exception will be thrown with a message
// where invalid_argument is class which defines different types of objects thrown as exception by reporting an invalid argument
if(h < 0.01)
{

throw invalid_argument("Height is less than 0.01.");
}
}
//used for initializing width value
void set_width(double w)
{
width = w;
//checks width value and if it is less than 0.01 then an invalid_argument exception will be thrown with a message
// where invalid_argument is class which defines different types of objects thrown as exception by reporting an invalid argument
if(w < 0.01)
{

throw invalid_argument("Width is less than 0.01.");
}
}
//used for initializing depth value

void set_depth(double d)
{
depth = d;
//checks width value and if it is less than 0.01 then an invalid_argument exception will be thrown with a message
// where invalid_argument is class which defines different types of objects thrown as exception by reporting an invalid argument
if(d < 0.01)
{

throw invalid_argument("Depth is less than 0.01.");
}
}
//returns height
double get_height()
{
return height;
}

double get_width()
{
return width;
}

double get_depth()
{
return depth;
}
//returns volume of box
double volume()
{

return height * width * depth;
}
//print the contents of object
void to_string()
{

cout << "Height:\t" << height << endl;
cout << "Width :\t" << width << endl;
cout << "Depth :\t" << depth << endl;

cout << endl;
}
};
int main()
{

Box b1, b2(9, 8, 3);//Box b1 calling default constructor and Box b2 calling parameterized constructor

cout << "Box b1:" << endl;
b1.to_string(); //print b1 contents

cout << "Box b2:" << endl;
b2.to_string();//print b2 contents

cout << "Volume of b1: " << b1.volume() << endl; //calculate volume of boxes b1 & b2
cout << "Volume of b2: " << b2.volume() << endl;
cout << endl;

cout << "Changing width of b2 to 0.3" << endl;
b2.set_width(0.90);//changing width of second box

cout << "Changing width of b2 to 0.90, width: " << b2.get_width() << endl;////changing width of second box again
cout << "Volume: " << b2.volume() << endl; //calling second box volume
cout << endl;
  
b1.resize(2.3, 1.5, 5.2); //resizing first box

cout << "After resizing b1:" << endl;
b1.to_string(); //printing box b1 contents after resizing its dimensions
cout << "New volume:" << endl;
cout << "Volume: " << b1.volume() << endl; //calculating volume of new box

try
{
cout << "If width is set under 0.01:" << endl;
b1.set_width(0.001);
}
//exception handler catches the exception thrown by set_width() function and handles it
catch(invalid_argument e)
{
cout << "0.01 is the minimum width for the box!" << endl;
}

return 0;
}