Question

Construct a C++ class named Rectangle that has floating-point data members named length and width.  The class should have a zero-argument constructor that initializes each data member to 0. It should have member functions named calcPerimeter() and calcArea() that calculate the perimeter and area of a rectangle respectively, a member function setLength() and setWidth() to set the length and width, member functions getLength() and getWidth() to return the length and width, and a member function showData() that displays the rectangle’s length, width, perimeter, and area. The class should use appropriate protection levels for the member data and functions. It should also follow “principles of minimalization”: that is, no member data should be part of a class unless it is needed by most member functions of the object.  A general rule of thumb is that “if you caneasily calculate it, don’t store it.”

Use your class in a program that creates an instance of a Rectangle (utilizing the zero-argument constructor), prompts a user for a length and width, calls the setLength() and setWidth() functions to set the rectangle’s length and width, and then calls showData() to display the resulting inputs, perimeter, and area. Your program should allow the user to enter rectangle dimensions until the user enters Ctrl-Z.  Be sure to include appropriate error checking.  Does a negative length or width make sense? No.  Therefore, you should ensure that the user only enters positive numbers. Also, does it make sense to enter “abc” as the length of a rectangle?  No, again.  Therefore, you should also ensure that the user enters numeric data for both length and width. Your code should be constructed such that separate files are used for the class header, class implementation, and driver program. Use good prompting, output labeling, and modularization in your program and class. Be sure to avoid using global variables in your program

Answer 1

Program Screenshot:

Rectangle.h

Rectangle.cpp

driver.cpp

Sample output:

Code to copy:

Rectangle.h

#ifndef RECTANGLE_H

#define RECTANGLE_H

#include <iostream>

using namespace std;

//define the class Rectangle

class Rectangle

{

private:

       // declare the floating - point data members named length and width.

       float length;

       float width;

public:

       //zero-argument constructor

       Rectangle();

       //declare the memeber functions.

       float calcPerimeter();

       float calcArea();

       void setLength(float len);

       void setWidth(float wid);

       float getLength();

       float getWidth();

       void showData();

      

};

#endif

Rectangle.cpp

#include "Rectangle.h"

//zero-argument constructor that initializes each data member to 0.

Rectangle::Rectangle()

{

       length = 0;

       width = 0;

}

//definition of the function calcPerimeter

//calculates the perimeter of the rectangle

float Rectangle::calcPerimeter()

{

       return 2 * (length + width);

}

//definition of the function calcArea

//calculates the area of the rectangle

float Rectangle::calcArea()

{

       return (length * width);

}

//definition of the function setLength

// sets the length

void Rectangle::setLength(float len)

{

       length = len;

}

//definition of the function setWidth

// sets the width

void Rectangle::setWidth(float wid)

{

       width = wid;

}

//definition of the function getLength

//returns the length

float Rectangle::getLength()

{

       return length;

}

//definition of the function getWidth

//returns the width

float Rectangle::getWidth()

{

       return width;

}

//definition of the function showData.

//displays the rectangle’s length, width, perimeter, and area.

void Rectangle::showData()

{

       cout << "The length of the rectange: " << getLength() << endl;

       cout << "The width of the rectange: " << getWidth() << endl;

       cout << "The perimeter of the rectange: " << calcPerimeter() << endl;

       cout << "The area of the rectange: " << calcArea() << endl;

}

Driver.cpp

#include "Rectangle.h"

bool EndOfInputStream(istream&);

int main()

{

       float length, width;

       //create an instance of a Rectangle

       Rectangle r1;

       //prompts a user for a length

       cout << "Enter length (Ctrl-Z to exit): ";

       cin >> length;

       //iterate a loop until the user enters Ctrl-Z

       //call the function EndOfInputStream() to test the input is Ctrl-Z

       while (!EndOfInputStream(cin))

       {

              //if the user is less than 0 or a string,

              //then print an error message and read again until user enter valid input.

              while (cin.fail() || length < 0)

              {

                     cout << "You must enter a positive number. Please try again." << endl;

                     cin.clear();

                     cin.ignore(numeric_limits<streamsize>::max(),'\n');

                     cout << "Enter length (Ctrl-Z to exit): ";

                     cin >> length;

              }

              //prompts a user for a width

              cout << "Enter width (Ctrl-Z to exit): ";

              cin >> width;

              //if the user is less than 0 or a string,

              //then print an error message and read again until user enter valid input.

              while (cin.fail() || width < 0)

              {

                     cout << "You must enter a positive number. Please try again." << endl;

                     cin.clear();

                     cin.ignore(numeric_limits<streamsize>::max(), '\n');

                     cout << "Enter width (Ctrl-Z to exit): ";

                     cin >> width;

              }

              //call the setLength() to set the rectangle’s length.

              r1.setLength(length);

              //call the setWidth() to set the rectangle’s width.

              r1.setWidth(width);

              cout << endl;

              //calls showData() to display the resulting inputs, perimeter, and area.

              r1.showData();

              cout << endl << endl;

              cout << "Enter length (Ctrl-Z to exit): ";

              cin >> length;

       }

       return 0;

}

//definition of the function EndOfInputStream().

bool EndOfInputStream(istream& input)

{

       bool endOfInput{ false };

       if (input.eof())

       {

              endOfInput = true;

       }

       return endOfInput;

}