Identifiers and keywords
- Identifiers are name given to various elements of program such as variables, functions, structures, unions,etc.
- Identifiers have same rules to construct as the rules for constructing variables names.
- Uppercase and lowercase letters can be used but have different meaning.
- eg. sum and SUM have same name but different meaning.
- INVALID Identifiers: basic-pay, d.a, h-t-a.
Keywords : Keywords are the reserved words that have standard, predefined meaning in c.
We should not have to use keywords to construct variable names .
Keywords in C:
continue, double, else, enum, extern, float,
for, goto, if, innto, long, register, return,
short, signed, sizeof, static, struct, switch,
typedef, union, unsigned,
void, volatile, while.
NOTE: Keywords are always written in lowercase.