Difference between namespace and class

A namespace and a class are both used to organize C++ programs, but they serve different purposes. A namespace groups related identifiers to avoid naming conflicts, whereas a class defines a user-defined type for creating objects.

• Namespaces help organize code and prevent name collisions.
• Classes encapsulate data and behavior into reusable objects.

Namespace

A namespace is a named scope that groups related identifiers such as variables, functions, and classes. It helps avoid conflicts when multiple libraries or modules contain identifiers with the same name.

• Groups related identifiers under a common name.
• Prevents naming conflicts between different libraries.
• Cannot be instantiated as an object.
• Can be reopened and extended across multiple declarations.

#include <iostream>
using namespace std;

namespace Math {
    int square(int x) {
        return x * x;
    }
}

int main() {
    cout << Math::square(5);
    return 0;
}

25

Explanation: The function square() belongs to the Math namespace and is accessed using the scope resolution operator (Math::).

Class

A class is a user-defined data type that encapsulates data members and member functions into a single unit. Objects are created from a class to represent entities with data and behavior.

• Used to create objects.
• Supports encapsulation through access specifiers.
• Can contain data members and member functions.
• Supports object-oriented features such as inheritance and polymorphism.

#include <iostream>
using namespace std;

class Student {
public:
    void display() {
        cout << "Student Object";
    }
};

int main() {
    Student s;
    s.display();
    return 0;
}

Student Object

Explanation: The class Student defines a user-defined type, and an object s is created to access its member function.

Difference Between Namespace and Class