C Tutorials
| Dat Types |
Data types used for declaring variables or functions of different types. The type of a variable determines how much space it occupies in memory for storage. The types in C can be classified as follows:
| Basic Types | Integers and Floating point types |
| Enumerated Types | Arithmetic types and they are used to define variables that can only be assigned certain discrete integer values throughout the program. |
| void Type | void indicates that no value is available. |
| Derived Types | Pounter, Array, Structure, Union and Function |
The array types and structure types are referred to collectively as the aggregate types. The type of a function specifies the type of the function's return value.
| Integer Types |
| Type | Size | 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 byte | -32,768 to 32,767 |
| unsigned short | 2 byte | 0 to 65,535 |
| long | 4 byte | -2,147,483,648 to 2,147,483,647 |
| unsigned long | 4 byte | 0 to 4,294,967,295 |
To get the exact size of a type or a variable on a particular platform, we can use the sizeof operator. The expressions sizeof(type) yields the storage size of the object or type in bytes. Following is an example to get the size of int type on any machine:
#include <stdio.h>
#include <limits.h>
void main()
{
printf("\nSize of int : %d", sizeof(int));
}
| Floating Point Types |
Type |
Size | 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. Following example will print storage space taken by a float type and its range values:
#include <stdio.h>
#include <float.h>
int main()
{
printf("\nStorage size for float : %d ", sizeof(float));
printf("\nMinimum float positive value: %E", FLT_MIN );
printf("\nMaximum float positive value: %E", FLT_MAX );
printf("\nPrecision value: %d", FLT_DIG );
return 0;
}
| Void Types |
The void type specifies that no value is available.
| Function return as void | There are various functions in C who do not return value or you can say they return void. A function with no return value has the return type as void. |
| Function arguments as void | There are various functions in C who do not accept any parameter. A function with no parameter can accept as a 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. |
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