What is the Singleton design pattern in C++ and Java?

What is the Singleton design pattern in C++ and Java?

The Singleton design pattern ensures a class has only one instance and provides a global point of access to it.

Can you give me an example of how to implement it in C++?

Sure! In C++, you can use a static member function to return the single instance of the class. Here's a simple example:

class Singleton {
private:
    static Singleton* instance;
    Singleton() {}  // Private constructor

public:
    static Singleton* getInstance() {
        if (!instance) {
            instance = new Singleton();
        }
        return instance;
    }
};
Singleton* Singleton::instance = nullptr;

How does it differ in Java?

In Java, you can use an enum to implement the Singleton pattern, which is thread-safe and prevents multiple instances. Here's an example:

public enum Singleton {
    INSTANCE;
    // Other methods can be added here
}

What are the advantages of using the Singleton pattern?

The advantages include controlled access to the single instance, reduced memory footprint, and global access to the instance.