Implement the Singleton Pattern

Problem Statement

Implement a `Database` class in C++ that strictly follows the Singleton design pattern using a static instance pointer and a private constructor. Ensure that multiple instantiations return the exact same object instance. Read an integer, set it as `value` on the first instance reference, get a second instance reference, and print its value to prove they share state.

Input Format

A single integer.

Output Format

Print the value retrieved from the second instance reference.

Constraints

None

Sample Input

Sample Output

Value: 42

Explanation

The Singleton pattern restricts the instantiation of a class to one single instance, sharing state globally. Returning a static local instance by reference is the modern thread-safe way in C++.

Starter Code

#include <iostream>

class Database {
    // Implement private constructor and static getInstance method
};

int main() {
    // Retrieve instance, set value, retrieve again, and print
    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

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