In C programming, an identifier is a name given to various entities such as variables, functions, structures, etc. It is a type of string of alphanumeric characters that always begins with either an alphabetic or underscore character. Identifiers must be unique and follow certain rules for naming, such as starting with a letter or underscore, and can contain letters, digits, and underscores. They cannot be the same as keywords, which are predefined, reserved words with special meanings to the compiler. Identifiers are used to uniquely identify entities within a program and are created to give a unique name to an entity to identify it during the execution of the program.
In summary, identifiers in C are essential for naming various entities within a program and play a crucial role in uniquely identifying these entities during program execution.
