C Data Types

By,
Praveen

Data types are used for declaring different types of variables and functions. This type of variable determines that how much space it taking in storage.
The types in C can be classified as follows −

Types & Description
 .Basic Types: - This is arithmetic type.
It is classified into 2 types –
a.Integer types
b.Floating point Types
2.Enumerated types: - This is also arithmetic types and used to define variables that used to assign certain type of discrete integer values.

3.Void type:- This type of data type indicates that there is no value available for return.
  
4.Derived types :- Derived types list are
(a) Pointer types,
(b) Array types,
(c) Structure types,
(d) Union types and
(e) Function types.   
Integer Types:
Following Table showing standard integer types and size with their range –
S.no     Type                    Size in bytes                      Range
1           Char                            1                      -128   to  127
2           unsigned char              1                           0   to  255
3           signed char                  1                      -128   to  127
4           int                               2                  -32,768   to  32,767
5           unsigned int                 2                           0   to  65,535
6           short                           2                  -32,768   to  32,767
7           unsigned short             2                           0   to  65,535
8           long                            4       -2,147,483,648   to   2,147,483,647
9           unsigned long              4                           0   to  4,294,967,295
Sizeof() operator :
To get the size of a type, sizeof() operator is used.
#include <stdio.h>
#include<conio.h>
#include <limits.h>
int main()
{
    int a=5;
    printf("size for int is : %d ", sizeof(int));
    return 0;
}
Output : size for int is : 2
Floating-Point Types
Following Table showing standard floating-point types and size with their range –
S. no    Type              Size in bytes                 Range                   Precision
1           float                     4                 1.2E-38  to  3.4E+38             6
2          double                  8                2.3E-308  to  1.7E+308          15
3         long double           10             3.4E-4932  to  1.1E+4932         19
Ex.
The header file <float.h> is used to allow to use values and other details of  binary representation of real numbers in programs.
The following example show that the storage space taken by a float type and its range values −
#include <stdio.h>
#include<conio.h>
#include <float.h>
int main()
{
    float min,max,dig;
    printf("size for float : %d \n", sizeof(float));
    printf("Minimum float positive value: %f\n", min );
    printf("Maximum float positive value: %f\n", max );
    printf("float place value: %d\n", dig );
    return 0;
}
The void Type
This void type used to specify that there is no value available to return.
Three kinds of situations of void type –
1.Function returns as void: There are various functions, they don’t return any value or return void. A function has no return value, has the return type as void.
Ex. void exit (int a);
2.Function arguments as void: A function that do not accept any parameter. This function accepts a void.
Ex. int rand(void);
3.Pointers to void: This (pointer of type void *) represents the address of an object, but not its type.
EX.  a memory allocation function void *malloc( size_t size );
returns a pointer to void .