References

A reference in C++ is an alias, or an alternative name, for an existing variable. Unlike a pointer, which stores a memory address, a reference acts as another name for the same piece of memory. You declare a reference using the ampersand (`&`) symbol. For example, `int original = 10; int& ref = original;`. Here, `ref` is a reference to `original`. Any operation performed on `ref` is actually performed on `original`. If you execute `ref = 20;`, the value of `original` will also become `20`. References have a few key properties that distinguish them from pointers. First, a reference must be initialized when it is declared. You cannot have an uninitialized reference. Second, once a reference is initialized to refer to a variable, it cannot be 'reseated' or changed to refer to a different variable. It will always be an alias for the original variable it was assigned to. Third, you don't need a special dereferencing operator to access the value; you just use the reference's name directly. Because of these properties, references are often considered simpler and safer than pointers. They are particularly useful for passing arguments to functions 'by reference', which allows the function to modify the original argument without the caller having to pass a memory address explicitly. This avoids making a copy of the argument, which can be a significant performance benefit for large objects.