Data types is simply used to declared variables or the functions. The variable type specifies that how much space it will occupy in the storage and how the bit pattern stored is interpreted. C defines the following five basic data types:
Except the type void, the basic data types may have various modifiers preceding them. A type modifier changes the meaning of the base type to more precisely fit a specific need. Here is the list of modifiers:
The int base type can be modified by signed, short, long, and unsigned. And the char type can be modified by signed and unsigned. You may also apply long to double.
Following table lists all the data types with their sizes and ranges :
| Type | Storage Size (in Bytes) | Minimal Range |
|---|---|---|
| char | 1 | -127 to 127 |
| unsigned char | 1 | 0 to 255 |
| signed char | 1 | -127 to 127 |
| int | 2 or 4 | -32,767 to 32,767 |
| unsigned int | 2 or 4 | 0 to 65,535 |
| signed int | 2 or 4 | -32,767 to 32,767 |
| short int | 2 | -32,767 to 32,767 |
| unsigned short int | 2 | 0 to 65,535 |
| signed short int | 2 | -32,767 to 32,767 |
| long int | 4 | -2,147,483,647 to 2,147,483,647 |
| long long int | 8 | -(263-1) to 263-1 |
| signed long int | 4 | -2,147,483,647 to 2,147,483,647 |
| unsigned long int | 4 | 0 to 4,294,967,295 |
| unsigned long long int | 8 | 264-1 |
| float | 4 | 1E-37 to 1E+37(six digits of precision) |
| double | 8 | 1E-37 to 1E+37(ten digits of precision) |
| long double | 10 | 1E-37 to 1E+37(ten digits of precision) |
Signed integers are important for a great many algorithms, but they only have half the absolute magnitude of their unsigned relatives. For instance, here 32,767 in binary is:
0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
When type modifier doesn't precede a basic type, then int is assumed. Let's look at the following table:
| specifier | is same as |
|---|---|
| signed | signed int |
| unsigned | unsigned int |
| long | long int |
| short | short int |
Since int data type has the different size on the different platform, so to get the exact or actual size of an int type or an int type variable on a particular platform, use the sizeof operator. The expressions sizeof(type) i.e., sizeof(int) tells the storage size of an object or type in bytes. Following example shows how to get the exact size of an int type on any platform:
#include<stdio.h>
#include<conio.h>
void main()
{
clrscr();
printf("Storage size of int: %d\n", sizeof(int));
getch();
}
Here is the sample output of the above C program:
