Data types
Data types are used to declare variables before using them.
The two basic uses of data type can be described as follows :-
1. It tells compiler what the variable name is.
2. It specifies what type of data variables will holds and the set of operations that can be
performed on this data.
Let us take a example to let you understand about the data type more in deep :-
Consider a light switch , it has a set of two values as on and off and two operations as turn on
and turn off.
For Example :-. int x;
Here int is a data type, which says only only int type of data can be stored here .
TYPES OF DATA TYPE :-
There are three type of data types.
1. Primary data types
2. User defined data types
3. Drived data types
PRIMITIVE DATA TYPE
In this data type ,a variable is a character or integer type or it is a
float type or double type . All these have its own different tyes.
EXAMPLE OF
PRIMITIVE DATA TYPE:- int, float, double, char .
int
Integers are whole numbers that can have both zero, positive and negative values but no decimal values. For example, 0, -5, 10
TO DECLARE AN INTEGER TYPE VARIABLE WE WOULD WRITE IT AS -
int a =15;
The size of int is usually 4 bytes (32 bits). And, it can take 232 distinct states from -2147483648 to 2147483647.
Float
To declare a floating point number we would write it as
float for example(1.1,2.7)
b=150.23;
- Float data type allows a variable to store decimal values.
- Storage size of float data type is 4. This also varies depend upon the processor in the CPU as “int” data type.
Char
To declare the character point number we would write it as
char Key='A'
here char is the data type(primitive data type) and he is a variable of which contains the
character type data i.e.,
- Character data type allows a variable to store only one character.
- Storage size of character data type is 1. We can store only one character using character data type.
DRIVED DATA TYPES :-
Derived datatypes are composed of fundamental datatypes. Some
fundamental datatypes as we discussed earlier i.e., primitive data type are:-- int, char, float,
void etc.
Derived datatypes are arrays, structures, pointers etc. ... Integers are used to store
integer type data, not the floating point number.
USER DEFINED DATA TYPE:-
A user-defined data type (UDT) is a data type that derived from
an existing data type. You can use UDT’s (user defined data Type) to extend the built-in types
already available and create your own customized data types.
FOR EXAMPLE :-- Structure , union, type definition and enumerated data types.
NOW let us see the how many storage does these data type take :--
| DATA TYPE | MEMORY (BYTES) | RANGE | FORMAT SPECIFIER |
|---|---|---|---|
| char | 1 | -128 to 127 or 0 to 255 | %c |
| unsigned char | 1 | 0 to 255 | %c |
| signed char | 1 | -128 to 127 | %c |
| int | 2 or 4 | -2,147,483,648 to 2,147,483,647 | %d |
| unsigned int | 2 or 4 | 0 to 65,535 or 0 to 4,294,967,295 | %d |
| int short | 2 | 32,768 to 32,767 | %hd |
| unsigned short int | 2 | 0 to 65,535 | %hu |
| long | 8 | 9223372036854775808 to 9223372036854775807 | %ld |
| unsigned long | 8 | 0 to 18446744073709551615 | %lu |
Floating-Point Types
The following table provide the details of standard floating-point types with storage sizes and
value ranges and their precision −
| DATA TYPE | MEMORY (BYTES) | RANGE | Precision |
|---|---|---|---|
| float | 4 | 1.2E-38 to 3.4E+38 | 6 decimal places |
| double | 8 | 2.3E-308 to 1.7E+308 | 15 decimal places |
| long double | 10 | 3.4E-4932 to 1.1E+4932 | 19 decimal places |
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