Keywords are pre-defined words in a C compiler. Each keyword is meant to perform a specific function in a C program.
Since keywords are referred as a name for compiler, they can’t be used as variable name because it has standard predefined specific meaning. Keywords should be written in lower case
In C programming around 32 words have been reserved as the keywords.
The meaning and working of these keywords are already known to the compiler and therefore, it can not be changed or modified.
The basic instructions are built up using a reserved set of words, such as main, for, if, while, default, double, extern, for, and int, etc.,