How do I detect and fix object slicing bugs?

Object slicing is a common issue in C++ that occurs when an object of a derived class is assigned to a variable of a base class type. This can lead to the loss of information specific to the derived class. Here’s how to detect and address object slicing bugs in your code.

Understanding Object Slicing

Object slicing happens when a derived class object is passed to a function that accepts a base class object, resulting in the derived portion of the object being "sliced off." For example:


    class Base {
        public:
            virtual void display() const { std::cout << "Base" << std::endl; }
    };
    
    class Derived : public Base {
        public:
            void display() const override { std::cout << "Derived" << std::endl; }
    };
    
    void func(Base b) {
        b.display(); // Object slicing occurs here
    }
    
    int main() {
        Derived d;
        func(d); // When invoking func, Derived is sliced to Base
    }

How to Fix Object Slicing

To prevent slicing, use pointers or references to base class objects instead of passing by value. This maintains the polymorphic behavior and avoids object slicing:


    void func(Base& b) {
        b.display(); // No slicing occurs
    }
    
    int main() {
        Derived d;
        func(d); // Passing by reference keeps the Derived class intact
    }

Best Practices

To avoid object slicing:

Always pass polymorphic objects by reference or pointer.
Use smart pointers to manage object lifetimes and memory automatically.

How do I detect and fix object slicing bugs?

Understanding Object Slicing

How to Fix Object Slicing

Best Practices

Popular Topics

Recent Languages

How do I detect and fix object slicing bugs?

Understanding Object Slicing

How to Fix Object Slicing

Best Practices

Related Questions

Popular Topics

Recent Languages