Data Types
Data types in C refers to an extensive system used for declaring variables or functions of different types. The type of variable determines how much space it occupies in storage and how the bit pattern stored is interpreted.
The data types can be classified as:
- Basic Types: They are arithmetic types and are further classified into (a) integer types and (b) floating-point types (c) void types.
- Derived Types: They include (a) Pointer types, (b) Array types, (c) Function types.
- User-defined Types: They are (a) Enumeration types (b) Structure types (c) Union types.
1. Basic Types: The fundamental data types are called basic data types.
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 on any machine.
#include <stdio.h>
#include <limits.h>
int main()
{
printf("Storage size for int : %d \n", sizeof(int));
return 0;
}
Storage size
for int : 4
int name;
int name, age;
unsigned int x;
int y;
Type |
Storage size |
Value range |
Precision
|
float |
4 byte |
1.2E-38 to 3.4E+38 |
6 decimal places |
double |
8 byte |
2.3E-308 to 1.7E+308 |
15 decimal places |
long double |
10 byte |
3.4E-4932 to 1.1E+4932 |
19 decimal places |
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. The following example prints the storage space taken by a float type and its range values:
#include <stdio.h>
#include <float.h>
int main()
{
printf("Storage size for float : %d \n", sizeof(float));
printf("Minimum float positive value: %E\n", FLT_MIN );
printf("Maximum float positive value: %E\n", FLT_MAX );
printf("Precision value: %d\n", FLT_DIG );
return 0;
}
Storage size for float : 4
Minimum float positive value: 1.175494E-38
Maximum float positive value: 3.402823E+38
Precision value: 6
float salary;
double price;
float normalizationFactor =22.422e4;
long a;
long long b;
long
double c;
short d;
- 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 the 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 cast to any data type.
- Pointer types
- Array types
- Function types
You will learn about these derived data types in a later chapter.
- Enumeration types
- Structure types
- Union types.
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