Data type In C

Although the term “Data Type” describes itself yet I will tell you in one sentence that “A data type defines all about the variable behavior”.

you can tell every detail(nature, limit, size) about a variable if you know about its data type.

1	signed short int input1;

So, input1 is an :

— Integer type variable

— Which holds +ve and -ve values

— Between range -32768 to +32767.

And all you can predict about input1 because of its data type signed short int.

Let’s say you are writing a program for two number addition.To write this program you must be clear about the user’s input behavior like –

— Type of Input Data i.e integer, decimal, positive, negative

— Range of input data

let’s assume as a user I will input

— Integer value only

— Positive and negative both

— Input data between -32,000 to +32,000

So as a programmer I will declare following variable at 32- bit platform –

— Input1 and Input2 —– > For storing user input in memory

— result ———————> to store the result of the operation

signed short int input1; /*memory size=2 byte ,data limit=-32768 to +32767*/

signed short int input2; /*memory size=2 byte ,data limit=-32768 to +32767*/

signed int Result; /*memory size=4 byte ,data limit=-2147483648 to +2147483647*/

Note:

Data type of Result is signed int to accept the correct result of extreme inputs of signed short int inputs.

If input1 =20000 , input2 = 20000

Result =40,000

40,000 is beyond the short int range.So Result has signed short int data type.

Data Types are mainly divided into three categories(Click On link for detail) –

See below classification diagram for detail.

Fundamental types	Memory Size	Range(for 32-bit platform)	Format Specifier
char	1 byte	-128 to +127	%c (%d for Numerical output)
signed char	1 byte	-128 to +127	%c (%d for Numerical output)
unsigned char	1 byte	0 to 255	%c (%u for Numerical output)
short int	2 byte	-32768 to 32767	%d
signed short int	2 byte	-32768 to 32767	%d
unsigned short int	2 byte	0 to 65535	%u
int	4 byte	-2147483648 to 2147483647	%d
signed int	4 byte	-2147483648 to 2147483647	%d
unsigned int	4 byte	0 to 4294967295	%u
long int	8 byte	-9223372036854775808 to 9223372036854775807	%ld
signed long int	8 byte	-9223372036854775808 to 9223372036854775807	%ld
unsigned long int	8 byte	0 to 18446744073709551615	%lu
float	4 byte	1.175494e-38 to 3.402823e+38	%f or %e(for exponential output)
double	8 byte	2.225074e-308 to 1.797693e+308	%lf or %le(for exponential output)
long double	16 byte	3.362103e-4932 to 1.189731e+4932	%Lf or %Le(for exponential output)
void	0 byte