Category: a. Basic Data Type

Keyword char is used for declaring character type variables. For example,

char test = 'h';

The size of the character variable is 1 byte.

float and double are used to hold real numbers.

float salary;
double price;

In C, floating-point numbers can also be represented in exponential. For example,

float normalizationFactor = 22.442e2;

What’s the difference between float and double?

The size of float (single precision float data type) is 4 bytes. And the size of double (double precision float data type) is 8 bytes.

Integers are whole numbers that can have both zero, positive and negative values but no decimal values. For example, 0, -5, 10

We can use int for declaring an integer variable.

int id;

Here, id is a variable of type integer.

You can declare multiple variables at once in C programming. For example,

int id, age;

The size of int is usually 4 bytes (32 bits). And, it can take 232 distinct states from -2147483648 to 2147483647.

There are the following data types in C language.

Types	Data Types
Basic Data Type	int, char, float, double
Derived Data Type	array, pointer, structure, union
Enumeration Data Type	enum
Void Data Type	void

The basic data types are integer-based and floating-point based. C language supports both signed and unsigned literals.

The memory size of the basic data types may change according to 32 or 64-bit operating system.

Let’s see the basic data types. Its size is given according to 32-bit architecture.

Data Types	Memory Size	Range
char	1 byte	−128 to 127
signed char	1 byte	−128 to 127
unsigned char	1 byte	0 to 255
short	2 byte	−32,768 to 32,767
signed short	2 byte	−32,768 to 32,767
unsigned short	2 byte	0 to 65,535
int	2 byte	−32,768 to 32,767
signed int	2 byte	−32,768 to 32,767
unsigned int	2 byte	0 to 65,535
short int	2 byte	−32,768 to 32,767
signed short int	2 byte	−32,768 to 32,767
unsigned short int	2 byte	0 to 65,535
long int	4 byte	-2,147,483,648 to 2,147,483,647
signed long int	4 byte	-2,147,483,648 to 2,147,483,647
unsigned long int	4 byte	0 to 4,294,967,295
float	4 byte
double	8 byte
long double	10 byte

As the name suggests, a Datatype defines the type of data being used. Whenever we define a variable or use any data in the C language program, we have to specify the type of the data, so that the compiler knows what type of data to expect.

For example, you may want to use a number like 1, 2, 100, or a decimal point number like 99.95, 10.5, or a text, like “Studytonight”, all these values are handled differently by the C language compiler, hence, we use data types to define the type of data used in any program.

C Datatypes

Broadly, there are 5 different categories of data types in the C language, they are:

Type	Example
Basic	character, integer, floating-point, double.
Derived	Array, structure, union, etc.
Enumeration	enums
Bool type	true or false
void	Empty value

C Primary Data types:

The C language has 5 basic (primary or primitive) data types, they are:

1. Character – ASCII character set or generally a single alphabet like ‘a’, ‘B’, etc.
2. Integer – Used to store whole numbers like 1, 2, 100, 1000, etc.
3. Floating-point – Decimal point or real numbers values like 99.9, 10.5, etc.
4. Double – Very large numeric values which are not allowed in Integer or Floating point type.
5. Void – This means no value. This data type is mostly used when we define functions.

There are different keywords to specify these data types, the keywords are:

Datatype	Keyword
Character	char
Integer	int
Floating-point	float
Double	double
Void	void