What is the difference between move and copy?

The main difference between move and copy is that when you move a file or folder, it is transferred from one location to another, and the original file is no longer in its original location. When you copy a file or folder, a duplicate is created in the new location, but the original file remains in its original location.

Move

- Moves the data from one location to another, removing it from the original location.
- Used to transfer ownership and memory space, not just copy data.
- Optimizes memory usage by avoiding duplication.
- Faster than copy, as it doesn't require extra memory to create copies.

Copy

- Creates a new copy of the data in a different location, leaving the original data unchanged.
- Involves creating a duplicate set of data, which can increase memory usage.
- Slower than move, as it requires extra memory to create the copy.

Key Differences

| Feature | Move | Copy |
|---|---|---|
| Data Transfer | Removes data from original location | Creates a new copy |
| Ownership | Transfers ownership | Maintains ownership |
| Memory Usage | Optimizes memory | Increases memory usage |
| Speed | Faster | Slower |

Example

```cpp
// Move
int a = 10;
int&& b = std::move(a); // Move 'a' to 'b', invalidating 'a'
std::cout << b << std::endl; // Output: 10

// Copy
int c = 10;
int& d = c; // Create a reference to 'c' (i.e., copy)
std::cout << d << std::endl; // Output: 10
```

In the move example, `a` is no longer valid after the move, and `b` now holds the value 10. In the copy example, both `c` and `d` refer to the same value 10, and modifying either variable will affect the other.