basic_string::reference
A type that provides a reference to an element stored in a string.
typedef typename allocator_type::reference reference;
Remarks
A type reference can be used to modify the value of an element.
The type is a synonym for allocator_type::reference.
For type string, it is equivalent to chr&.
Example
See the example for at for an example of how to declare and use reference.
Requirements
Header: <string>
Namespace: std