C-Data Types

Data Types

A  C language programmer has to tell the system before-hand, the type of numbers or characters he is using in his program. These are data types. There are many data types in C language. A C programmer has to use appropriate data type as per his requirement.
C language data types can be broadly classified as

  • Primary data type
  • Derived data type
  • User defined data type

Primary data type

All C Compilers accept the following fundamental data types

 

1.

 

Integer

 

int

 

2.

 

Character

 

char

 

3.

 

Floating Point

 

float

 

4.

 

Double precision floating point

 

double

 

5.

 

Void

 

void

 

 

 

The size and range of each data type is given in the table below

 

DATA TYPE

 

RANGE OF VALUES

 

char

 

-128 to 127

 

Int

 

-32768 to +32767

 

float

 

3.4 e-38 to 3.4 e+38

 

double

 

1.7 e-308 to 1.7 e+308

 

 

Integer Type:

Integers are whole numbers with a machine dependent range of values. A good programming language as to support the programmer by giving a control on a range of numbers and storage space. C has 3 classes of integer storage namely short int, int and long int. All of these data types have signed and unsigned forms. A short int requires half the space than normal integer values. Unsigned numbers are always positive and consume all the bits for the magnitude of the number. The long and unsigned integers are used to declare a longer range of values.

Floating Point Types:

Floating point number represents a real number with 6 digits precision. Floating point numbers are denoted by the keyword float. When the accuracy of the floating point number is insufficient, we can use the double to define the number. The double is same as float but with longer precision. To extend the precision further we can use long double which consumes 80 bits of memory space.

Void Type:

Using void data type, we can specify the type of a function. It is a good practice to avoid functions that does not return any values to the calling function.

Character Type:

A single character can be defined as a defined as a character type of data. Characters are usually stored in 8 bits of internal storage. The qualifier signed or unsigned can be explicitly applied to char. While unsigned characters have values between 0 and 255, signed characters have values from –128 to 127.


Size and Range of Data Types on 16 bit machine.

 

type

 

SIZE (Bits)

 

Range

 

Char or Signed Char

 

8

 

-128 to 127

 

Unsigned Char

 

8

 

0 to 255

 

Int or Signed int

 

16

 

-32768 to 32767

 

Unsigned int

 

16

 

0 to 65535

 

Short int or Signed short int

 

8

 

-128 to 127

 

Unsigned short int

 

8

 

0 to 255

 

Long int or signed long int

 

32

 

-2147483648 to 2147483647

 

Unsigned long int

 

32

 

0 to 4294967295

 

Float

 

32

 

3.4 e-38 to 3.4 e+38

 

Double

 

64

 

1.7e-308 to 1.7e+308

 

Long Double

 

80

 

3.4 e-4932 to 3.4 e+4932

 

 

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