 # What are Identifiers in c language?

## Introduction:

According to humans, languages are the way of communication between two people but according to computer technology languages are the way of communication between users and machines.

Like this c language is the way in which we will express our thoughts to the machines.

Remember when you are in school and you are studying the English language then at first you started with alphabets similarly here in c language we have to start with the basic letters of c language which are consist of alphabets, numbers and some special characters.

In the next step, you will start to make words here in c language words normally known as identifiers. In c language, the identifiers categorize into three categories such as –

1.constant

2.variable

3.keywords

Once we learn to make words in the next steps we have to make sentences, in c language sentences are known as instruction.

We will definitely learn these instructions in the later article. But here in this article, we will discuss the types of identifiers in language.

## Types of identifiers in c language :

### Constants :

In mathematics, a constant is something whose value is unchanged. But here in c language, a constant definition is something different, here any information is known as constant.

When we create some software then it has only one intention that we can manage our information, every software manages some information, this information calls constant.

We can also say that the data,information and constant all are the same thing.

In c language there are normally two types of constants one is primary constants and another is secondary constant.

Primary constant divide into three categories integer, real, and character, and on the other hand the second constant divide into six categories as an array, string, pointer, union, structure, enumerator.

Primary constants:

### Integer :

Integer numbers are those numbers that do not consist of points. For example, -50 is an example of an integer number, 20 is an integer constant even 0 is also an integer constant.

### Real :

Generally, real numbers are those numbers that are consistent with points. For example-20.1 is an example of a real constant,3.56 is an example of a real constant,2.0 is also an example of a real constant.

In mathematics, there is no difference between 2 and 2.0 but in c programming 2 and 2.0 both are not similar if we write 2 then that considered as an integer constant and if we write 2.0 then that considered as real numbers.

### Character :

Character constants are those constants which are consist with single quotes.

Such as ‘a’ is an example of a character constant, ‘p’ is also a character constant but if we remove these single quotes then these do not character constant. If we write ‘2’ then that is also not an integer constant it is actually a character constant. But ‘-3’ is not a character constant because the condition of a character constant is that character constant only needs one character here is two characters one is – and another is 3.

Secondary constants:

Secondary constants are those constants which are consist with the help of primary constants.

### Array :

If we define that what is array then we can say that the linear collection of similar elements is called arrays. An array known as a subscript variable. It is a group of variables. An array is 0 indexed which means the array started from 0.

### String :

Strings are the sequence of characters terminated by the null characters. Strings are normally present within the double-quotes. Ascii code of null character is 0.

### Pointers :

Pointer is a variable that consists of the address of other variables. The pointer always consumes two bytes of memory, according to dos base architecture the highest address will be 65535 and its binary is 16 times 1.

### Structure :

Through structure, we can create a group of variables. It is a collection of dissimilar elements. Through structure, we can create a new data type.

### Union:

It is like structure, except it allows someone to define variables that share storage space. Declaring it means creating a new data type.

### Enumerator :

We know that there are normally 2 types of data type primitive data type and nonprimitive data type. There are three ways in which we can create non-primitive data type 1.structure 2.union 3.enumerator.

### Variables :

Normally variables are the names of the locations of memory where we store data.

Normally if we declare any variable into our program then that consumes memory in our ram.

Although there are some rules by which we can define a variable. Variable is any combination of alphabets, digit, and underscore. And a valid variable name cannot start with any digit. We will read about the variables in later articles.

### Keywords :

In any programming, language keywords are the preserve words or predefined words. Normally there are 32 keywords in a c programming language such as-

auto,double,goto,signed,unsigned,break,default,if,sizeof,void,case,enum,int,static,volatile,char,else,long,struct,while,const,for,return,typedef,do,float,short,union.

These keywords helps us to create a better program.

Conclusion: