What is Data types in C Programming Language?
Well, Data types in C refers to an extensive system used for declaring variables and functions of different types. The type of a variable determines how much space it occupies in storage and how the bit pattern for stored data is interpreted.
Data types in C or any programming language is something which specifies how to enter data into programs and what type of data to enter. C language has some predefined set of data types to handle various kinds of data that you can use in your program. These data types have different storage capacities.
Types Of Data types in C language
There are various statements on how many Data types in C to be considered. In my opinion, there are four Data types in C that you should consider.
But, you can categorise these four data types in two broad category, PRIMARY and Derived Data types in C.
BASIC Data types in C
They are arithmetic types and are further classified into integer types and floating-point types.
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ENUMERATED Data types in C
They are again arithmetic types and they are used to define variables that can only assign certain discrete integer values throughout the program.
VOID Data types in C
The type specifier void indicates that no value is available.
Derived Data types in C
Derived data types are nothing but primary data types but a little twisted or grouped together like an array, structure, union, and pointer.
The array types and structure types are referred collectively as the aggregate types. The type of a function specifies the type of the function’s return value. We will see the basic types in the following section, whereas other types will be covered in the upcoming chapters.
Character type
Character types are used to store characters value.
Size and range of Integer type on a 16-bit machine
| Type | Size(bytes) | Range |
|---|---|---|
| char or signed char | 1 | -128 to 127 |
| unsigned char | 1 | 0 to 255 |
Integer Types
The following table provides the details of standard integer types with their storage sizes and value ranges −
| Type | Storage size | Value range |
|---|---|---|
| char | 1 byte | -128 to 127 or 0 to 255 |
| unsigned char | 1 byte | 0 to 255 |
| signed char | 1 byte | -128 to 127 |
| int | 2 or 4 bytes | -32,768 to 32,767 or -2,147,483,648 to 2,147,483,647 |
| unsigned int | 2 or 4 bytes | 0 to 65,535 or 0 to 4,294,967,295 |
| short | 2 bytes | -32,768 to 32,767 |
| unsigned short | 2 bytes | 0 to 65,535 |
| long | 4 bytes | -2,147,483,648 to 2,147,483,647 |
| unsigned long | 4 bytes | 0 to 4,294,967,295 |
To get the exact size of a type or a variable on a particular platform, you can use the sizeof operator. The expressions sizeof(type) yields the storage size of the object or type in bytes. Given below is an example to get the size of int type
#include <stdio.h>
#include <limits.h>
int main()
{
printf("Storage size for int : %d \n", sizeof(int));
return 0;
}
When you compile and execute the above program, it produces the following result on Windows on which I am running:
OUTPUT: Storage size for int: 4
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Floating-Point Types
Floating types are used to store real numbers.
Size and range of Integer type on a 16-bit machine
| Type | Size(bytes) | Range |
|---|---|---|
| Float | 4 | 3.4E-38 to 3.4E+38 |
| double | 8 | 1.7E-308 to 1.7E+308 |
| long double | 10 | 3.4E-4932 to 1.1E+4932 |
The header file float.h defines macros that allow you to use these values and other details about the binary representation of real numbers in your programs
#include <stdio.h>
#include <float.h>
int main()
{
printf("Storage size for float : %d \n", sizeof(float));
return 0;
}
OUTPUT: Storage size for float: 4
The void Type
Function returns as void
There are various functions in C which do not return any value or you can say they return void. A function with no return value has the return type as void. For example, void exit (int status);
Function arguments as void
There are various functions in C which do not accept any parameter. A function with no parameter can accept a void. For example, int rand(void);
Pointers to void
A pointer of type void * represents the address of an object, but not its type. For example, a memory allocation function void *malloc( size_t size ); returns a pointer to void which can be casted to any data type.