C++ Smart Pointers Tutorial

What Are Smart Pointers?

Smart pointers are wrapper classes over raw pointers that ensure proper resource cleanup, preventing memory leaks.

Types of Smart Pointers

• std::unique_ptr: Owns and manages a single resource.
• std::shared_ptr: Allows multiple shared ownerships of a resource.
• std::weak_ptr: Avoids circular references when used with std::shared_ptr.

Usage Examples

Unique Pointer

#include <memory>
#include <iostream>

int main() {
    std::unique_ptr<int> ptr = std::make_unique<int>(10);
    std::cout << *ptr << std::endl; // Outputs: 10
    return 0;
}
                

Shared Pointer

#include <memory>
#include <iostream>

int main() {
    std::shared_ptr<int> ptr1 = std::make_shared<int>(20);
    std::shared_ptr<int> ptr2 = ptr1; // Shared ownership
    std::cout << *ptr2 << std::endl; // Outputs: 20
    return 0;
}
                

Weak Pointer

#include <memory>
#include <iostream>

int main() {
    std::shared_ptr<int> shared = std::make_shared<int>(30);
    std::weak_ptr<int> weak = shared; // Does not increase reference count
    if (auto locked = weak.lock()) {
        std::cout << *locked << std::endl; // Outputs: 30
    }
    return 0;
}
                

Benefits of Smart Pointers

• Automated memory management.
• Prevent dangling pointers.
• Reduce the risk of memory leaks.