C++ Plus Operator Overloading

Introduction

In this lab, you will learn how to demonstrate the concept of + operator overloading in C++ programming language. Operator overloading is a feature in C++ that allows a single operator or symbol to be used with different meanings, depending on the context in which it is used. In this lab, we will show how to add two Cuboid objects using the + operator.

Create a new C++ file

Create a new C++ file named main.cpp in the ~/project directory.

cd ~/project
touch main.cpp

Write code to demonstrate + operator overloading

Add the following code to main.cpp to create a class named Cuboid that represents a three-dimensional rectangular solid:

#include <iostream>

using namespace std;

//defining the class Cuboid to demonstrate the concept of Plus Operator Overloading in CPP
class Cuboid {
    //Declaring class member variables as public to access from outside the class
    public:
        double length; // Length of Cuboid
        double breadth; // Breadth of Cuboid
        double height; // Height of Cuboid

        public:
        double getVolume(void) {
            return length * breadth * height;
        }
        void setLength(double l) {
            length = l;
        }

        void setBreadth(double b) {
            breadth = b;
        }

        void setHeight(double h) {
            height = h;
        }

        // Overload + operator to add two Cuboid objects with each other.
        Cuboid operator + (const Cuboid & c) {
            Cuboid cuboid;
            cuboid.length = this -> length + c.length;
            cuboid.breadth = this -> breadth + c.breadth;
            cuboid.height = this -> height + c.height;
            return cuboid;
        }
};

Define the main function

Add the following code to main.cpp to implement the main function that creates three Cuboid objects, sets their dimensions, calculates their volumes, adds two of the objects, and prints the dimensions and volume of the resulting cuboid object:

//Defining the main method to access the members of the class
int main() {

    cout << "\n\nWelcome to LabEx :-)\n\n\n";
    cout << " =====  Program to demonstrate the Plus Operator Overloading, in CPP  ===== \n\n";

    //Declaring the Class objects to access the class members
    Cuboid c1;
    Cuboid c2;
    Cuboid c3;

    //To store the volume of the Cuboid
    double volume = 0.0;

    // Setting the length, breadth and height for the first Cuboid object: c1
    c1.setLength(3.0);
    c1.setBreadth(4.0);
    c1.setHeight(5.0);

    // Setting the length, breadth and height for the second Cuboid object: c2
    c2.setLength(2.0);
    c2.setBreadth(5.0);
    c2.setHeight(8.0);

    // Finding the Volume of the first Cuboid: c1
    cout << "Calling the getVolume() method to find the volume of Cuboid c1\n";
    volume = c1.getVolume();
    cout << "Volume of the Cuboid c1 is : " << volume << "\n\n\n";

    // Finding the Volume of the first Cuboid: c1
    cout << "Calling the getVolume() method to find the volume of Cuboid c2\n";
    volume = c2.getVolume();
    cout << "Volume of the Cuboid c2 is : " << volume << "\n\n\n";

    // Adding the two Cuboid objects c1 and c2 to form the third object c3:
    c3 = c1 + c2;

    // Printing the dimensions of the third Cuboid: c3
    cout << "Length of the Cuboid c3 is : " << c3.length << endl;
    cout << "Breadth of the Cuboid c3 is : " << c3.breadth << endl;
    cout << "Height of the Cuboid c3 is : " << c3.height << endl;

    // Finding the Volume of the third Cuboid: c3
    cout << "\n\nCalling the getVolume() method to find the volume of Cuboid c3\n";
    volume = c3.getVolume();
    cout << "Volume of the Cuboid c3 is : " << volume << endl;
    cout << "\n\n\n";

    return 0;
}

Compile and run the code

Use the following command to compile and run the code:

g++ main.cpp -o main && ./main

You will see the following output:

Welcome to LabEx :-)


 =====  Program to demonstrate the Plus Operator Overloading, in CPP  =====

Calling the getVolume() method to find the volume of Cuboid c1
Volume of the Cuboid c1 is : 60



Calling the getVolume() method to find the volume of Cuboid c2
Volume of the Cuboid c2 is : 80



Length of the Cuboid c3 is : 5
Breadth of the Cuboid c3 is : 9
Height of the Cuboid c3 is : 13


Calling the getVolume() method to find the volume of Cuboid c3
Volume of the Cuboid c3 is : 585

Summary

In this lab, you learned how to demonstrate the concept of + Operator Overloading in C++ programming language. Operator overloading is a powerful and useful feature of C++ that allows you to use an operator with different meanings in different contexts. By overloading the + operator, you can add two Cuboid objects with each other.