basic_string::const_reference
A type that provides a reference to a const element stored in a string for reading and performing const operations.
typedef typename allocator_type::const_reference const_reference;
Remarks
A type const_reference cannot be used to modify the value of an element.
The type is a synonym for allocator_type::const_reference. For string type, it is equivalent to const char&.
Example
See the example for at for an example of how to declare and use const_reference.
Requirements
Header: <string>
Namespace: std