Variables and Data type

Variable

In C it declares the type of variables by the datatype will come.

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Variable: A name to a memory location, declared by writing type variable_name;

                    Ex: int a;

                           int b;

Rules for defining the variable in C

Can contain alphabets, digits, and underscore (_)

A variable name can start with an alphabets only.

NO whitespace & reserved keywords is allowed

valid variables names: int rishav, float rishav 123, char _rishav34

invalid variable name: $rishav, int 77rishav, char long;

Data type

Basic Data type: int(%d), char(%c), float(%f), double

Derived Datatype: array, pointer, structure, union

Enumeration data type: emum

void Data type: void  (void means empty in C)

Data type	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 to 2,147,483,647
Signed long int	4 byte	-2,147,483 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

 Ex: char c = 'c' ;

hence it will take in 4 GB RAM (memory) {4 x 1024x 1024x 1024x 1024}bits

If you want to chech the size of the character👇

#include <stdio.h>

int main()

{

    printf("%lu", sizeof(int));

    return 0;

}

Basic operators and functions

We can use [+, -, *, /] in language C

Ex:👇

printf("%d", 3+7);

output👉(10)