basic_string::npos
An unsigned integral value initialized to –1 that indicates either "not found" or "all remaining characters" when a search function fails.
Syntax
static const size_type npos = -1;
Remarks
When the return value is to be checked for the npos value, it might not work unless the return value is of type size_type and not either int or unsigned.
Example
See the example for find for an example of how to declare and use npos.
Requirements
Header: <string>
Namespace: std