Type specifiers and type qualifiers in C .

[Humble]

There are type specifiers and type qualifiers in C .. “enum” , “void”..etc are examples of type specifiers and “volatile”, “const” etc are examples for type qualifiers..

enum:

Enumarated data or enum is one type specifier which allows you to define a fixed set of words that a variable of type enum can take as its value. The words are assigned integer values by the compiler so that code can compare enum variables.

void :

“void” bascially represent an empty area, but please note that its not invalid. void can be used when you prototype a function which returns nothing , when declaring a pointer or when declaring a variable ( void variables cannot be used in any way, so does not make sense ).

Regarding void pointers refer # https://humblec.com/forums/topic/void-pointer-in-c/

volatile:

The volatile keyword ensures that the variable is fetched from memory on every access. Really useful in case of memory-mapped variables.

*) Compiler will not optimize those variables
*) Always latest copy is read
*) Different programs or executions can access this shared variable without any issue.
*) In other way it convey that , this is getting changed autonomously.
*) Volatile variables are also flagged by the compiler as not to be stored in read-only memory.

const:

‘const’ type qualifier stands for “constant objects”. This type of variable must be assigned a value once and once only. More or less think that it might be in read-only memory. The reserved word const is, like static and volatile, a data type qualifier that can be applied to many different data types. It declares a variable to be a constant, whose value cannot be reassigned. A const must be assigned a value when it is declared.

Any attempt to assign a new value to a const variable will result in a compile-time error.

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