[C] Data Type

Data type in C

 

 

integer 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	8 bytes	-9223372036854775808 to 9223372036854775807
unsigned long	8 bytes	0 to 18446744073709551615

'limits.h' have data of limit numbers of inter types.

INT_MAX, INT_MIN

USHRT_MAX, USHRT_MIN     ect.

 

 

float types

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

 

 

void types

Types and Description

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.

 

 

 

typedef

 

'typedef' is a reserved keyword in the C and C++ programming languages. It is used to create an alias name for another data type.

typedef unsigned int ui;
ui a; // same as 'unsigned int a;'

 

 

 

type casting

 

· (type) variable

· (type) value

 

#include <stdio.h>
 
int main()
{
    int num1 = 32;
    int num2 = 6;
    float num3;
 
    num3 = num1 / num2;      // Compile error occurs
    printf("%f\n", num3);    // 5.000000
 
    num3 = (float)num1 / num2;    // cast 'num1' to float type
    printf("%f\n", num3);         // 5.333333
 
    return 0;
}