Datatype in C:-

Data type	Size (Bytes)	Range	Format Specifiers
Char	1	– 128 to 127	%c
Unsigned char	1	0 to 255	%c
Short or int	2	– 32,768 to z32, 767	%i or %d
Unsigned int	2	0 to 655355	%u
Float	4	3.4e – 38 to +3.4e +38	%f or %g
Long	4	2147483648 to 2147483647	%ld
Unsigned long	4	0 to 4294967295	%lu
Double	8	1.7e – 308 to 1.7e+308	%lf
Long double	10	3.4e – 4932 to 1.1e+4932	%lf

Note:-

In the little-endian system, the addresses are always in present  ABCD and data is stored in DCBA order

In big-endian system addresses are always in ABCD and data is stored in ABCD order

Cycle is not present in float or double types but present in integer and character data type.

Increments the value of a float or double variable beyond its maximum range that is +INF and beyond it minimum range is –INF

The  minimum  octal  character  constant  is  ‘\000’  and  maximum  octal  character constant is ‘\377’

Very first escape sequence character is ‘\a’ and last escape sequence character is ‘\r’

Float data always stores in memory mantissa and exponent format

Enum data types create a sequence sets of integral constants and there is no cycle present in enum data type

BCPL is a typeless language

When the language is able to produce a new data-type that is called extensibility

Typedef creates a new name but does not create a new type

The process of byte ordering is known as endianness

32 bits recurring binary of a float is always lesser than 64 bits recurring binary of a float

When a signed negative integer compared with an unsigned integer, its binary level of variable is compared but  not their value level

In float or double data types  Signed and unsigned modifiers are not allowed.

All constants in C are Rvalue category of objects

All escape sequence characters are octal character constants.

The null string constant size is 1 byte.

‘\0’ is null character constant whose ASCII value is 0

Variable

Variable name us a data name and it is used for storing the data value.T he variable size should be changed at the time of execution.

The variable name should begin with the alphabet or underscore character

Variable allocates memory.

Constant

Constant is a number or a character.

The constant value cannot be changed and constant value always places on the right side of the equality operator.

Keywords in C

Keyword is the reserved word used by compile

Keyword cannot be the name of an identifier.

Keywords in C

A=auto

B=break

C=const,char,case,continue

D=do,double,default

E=else,enum,extern

F=float, for

G=go to

I=int,if

L=long

R=return,registor

S=shor,signed,sizeof,static,switch,struct

T=typed of

U=union,unsigned

V=void,volatile

W=while

Identifier

Function name and variable name in  a programme called identifier.

Endianness is a process of byte ordering

Also Read:- What is C

Also Read:-Intresting fact about c

Also Read:-Structure of C program