A keyword is a reserved word. Keywords are words that have special meaning to the C compiler. There are 32 reserved words (keywords) in the C language.
Keywords are predefined, reserved words used in programming that have special meanings to the compiler.
Keywords are part of the syntax and they cannot be used as an identifier. You cannot use it as a variable name, constant name, etc.
keywords are not available for re-definition.
auto | double | int | struct |
break | else | long | switch |
case | enum | register | typedef |
char | extern | return | union |
continue | for | signed | void |
do | if | static | while |
default | goto | sizeof | volatile |
const | float | short | unsigned |