Data types

Declaration of variable names does two things

• it tells the compiler what the variable name is
• specifies what type of data the variable will hold

So it is mandatory that each variable should belong to a particular data type. C supports different data types like integer, character, float, double, etc.

Data type	Size on a 16 bit machine	Range
char	1 byte or 8 bits	-128 to 127
signed char	1 byte	-128 to 127
unsigned char	1 byte	0 to 255
short int or short	1 byte	-128 to 127
int	2 bytes	-32768 to 32767
unsigned int	2 bytes	0 to 65535
long int or long	4 bytes	-2,147,483,648 to 2,147,483,647
unsigned long int	4 bytes	0 to 4,294,967,295
float	4 bytes	3.4E-38 to 3.4 E+38
double	8 bytes	1.7E-308 to 1.7E+308
long double	10 bytes	3.4E-4932 to 1.1E+4932

Example of declaring variables

int a=20,b=20,c;

int a=10;

int b=9;

int c=20;

float c=3.5;

char a =’A’;

long int al or long a;

short int b or short b;

double c;

long double c;