How do I write copy constructors safely in C++?

In C++, a copy constructor is a special constructor used to create a new object as a copy of an existing object. Writing a safe copy constructor is essential to avoid issues such as double deletions, memory leaks, and data corruption. A well-designed copy constructor implements the Rule of Three (or the Rule of Five in C++11), ensuring that memory management is properly handled. Here are the key aspects of writing a safe copy constructor:

Make sure to allocate new memory for the copied object.
Copy the values from the existing object to the new object.
Prevent self-assignment by checking if the current object is the same as the one being copied.

Example of a Safe Copy Constructor


        class MyClass {
        private:
            int* data; // Pointer to an int array
            size_t size; // Size of the array

        public:
            // Constructor
            MyClass(size_t s) : size(s) {
                data = new int[size];
            }

            // Copy Constructor
            MyClass(const MyClass& other) {
                // Allocate new memory
                size = other.size;
                data = new int[size];
                // Copy the data
                for (size_t i = 0; i < size; i++) {
                    data[i] = other.data[i];
                }
            }

            // Destructor
            ~MyClass() {
                delete[] data;
            }

            // Assignment operator
            MyClass& operator=(const MyClass& other) {
                if (this == &other) return *this; // self-assignment guard

                delete[] data; // Free existing resource
                size = other.size;
                data = new int[size]; // Allocate new memory
                for (size_t i = 0; i < size; i++) {
                    data[i] = other.data[i]; // Copy the data
                }
                return *this;
            }
        };

How do I write copy constructors safely in C++?

Example of a Safe Copy Constructor

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How do I write copy constructors safely in C++?

Example of a Safe Copy Constructor

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