Explain the concept of move semantics in programming and how it differs from copying objects.

Move semantics is a mechanism in C++ (starting from C++11) that allows efficient transfer of resources from one object to another without copying.

Difference from copying:

• When copying, a new object is created with duplicated data (e.g., all fields are copied).
• When moving, resources (e.g., pointers to dynamic memory) are transferred from the source object to the new one, leaving the original object in a valid but 'empty' state.

This is especially useful for objects that own resources (memory, files, sockets) to avoid the cost of deep copying.

Example:

#include <iostream>
#include <vector>

class Buffer {
    std::vector<int> data;
public:
    Buffer(size_t size) : data(size) {}

    // Copy constructor
    Buffer(const Buffer& other) : data(other.data) {
        std::cout << "Copy constructor called\n";
    }

    // Move constructor
    Buffer(Buffer&& other) noexcept : data(std::move(other.data)) {
        std::cout << "Move constructor called\n";
    }
};

int main() {
    Buffer buf1(100);
    Buffer buf2 = buf1;      // copying
    Buffer buf3 = std::move(buf1); // moving
}

Output:

Copy constructor called
Move constructor called

Thus, move semantics can improve performance by avoiding unnecessary copies.