The tokens with fixed meaning are called keywords in C. Keywords are reserved by the C, their meanings cannot be changed. Keywords cannot be used as identifiers.
Keywords in C
There are only 32 keywords in C Programming.
| int | void |
| auto | double |
| break | else |
| case | enum |
| char | extern |
| const | float |
| continue | for |
| default | goto |
| do | if |
| struct | long |
| switch | register |
| typedef | return |
| union | short |
| unsigned | signed |
| sizeof | volatile |
| static | while |