Data Types & Expressions

 

Data Types in C

Each variable in C has an associated data type. It specifies the type of data that the variable can store like integer, character, floating, double, etc. Each data type requires different amounts of memory and has some specific operations which can be performed over it. The data type is a collection of data with values having fixed values, meaning as well as its characteristics.

The data types in C can be classified as follows:

Types

Description

Primitive Data Types

Primitive data types are the most basic data types that are used for representing simple values such as integers, float, characters, etc.

User Defined Data Types

The user-defined data types are defined by the user himself.

Derived Types

The data types that are derived from the primitive or built-in datatypes are referred to as Derived Data Types.

 

Different data types also have different ranges up to which they can store numbers. These ranges may vary from compiler to compiler. Below is a list of ranges along with the memory requirement and format specifiers on the 32-bit GCC compiler.

Data Type 
 

Size (bytes) 
 

Range
 

Format Specifier 
 

short int 
 

2 

-32,768 to 32,767 

%hd 

unsigned short int 
 

2 

0 to 65,535 

%hu 

unsigned int 
 

4 

0 to 4,294,967,295 

%u 

int 
 

4 

-2,147,483,648 to 2,147,483,647 

%d 

long int 
 

4 

-2,147,483,648 to 2,147,483,647 

%ld 

unsigned long int 
 

4 

0 to 4,294,967,295 

%lu 

long long int 
 

8 

-(2^63) to (2^63)-1 

%lld 

unsigned long long int 
 

8 

0 to 18,446,744,073,709,551,615 

%llu 

signed char 
 

1 

-128 to 127 

%c 

unsigned char 
 

1 

0 to 255 

%c 

float 
 

4 

1.2E-38 to 3.4E+38

%f 

double 
 

8 

1.7E-308 to 1.7E+308

%lf 

long double 
 

16 

3.4E-4932 to 1.1E+4932

%Lf 

 

Note: The long, short, signed and unsigned are datatype modifier that can be used with some primitive data types to change the size or length of the datatype.

The following are some main primitive data types in C:

Ø  Integer Data Type

The integer datatype in C is used to store the integer numbers(any number including positive, negative and zero without decimal part). Octal values, hexadecimal values, and decimal values can be stored in int data type in C. 

  • Range:  -2,147,483,648 to 2,147,483,647
  • Size: 4 bytes
  • Format Specifier: %d

Syntax of Integer

int var_name;

Ø  Character Data Type

Character data type allows its variable to store only a single character. The size of the character is 1 byte. It is the most basic data type in C. It stores a single character and requires a single byte of memory in almost all compilers.

  • Range: (-128 to 127) or (0 to 255)
  • Size: 1 byte
  • Format Specifier: %c

Syntax of char

The char keyword is used to declare the variable of character type:

char var_name;

Ø  Float Data Type

In C programming float data type is used to store floating-point values. Float in C is used to store decimal and exponential values. It is used to store decimal numbers (numbers with floating point values) with single precision.

  • Range: 1.2E-38 to 3.4E+38
  • Size: 4 bytes
  • Format Specifier: %f

Syntax of float

The float keyword is used to declare the variable as a floating point:

float var_name;

Ø  Double Data Type

A Double data type in C is used to store decimal numbers (numbers with floating point values) with double precision. It is used to define numeric values which hold numbers with decimal values in C.

The double data type is basically a precision sort of data type that is capable of holding 64 bits of decimal numbers or floating points. Since double has more precision as compared to that float then it is much more obvious that it occupies twice the memory occupied by the floating-point type. It can easily accommodate about 16 to 17 digits after or before a decimal point.

  • Range: 1.7E-308 to 1.7E+308
  • Size: 8 bytes
  • Format Specifier: %lf

Syntax of Double

The variable can be declared as double precision floating point using the double keyword:

double var_name;

Ø  Void Data Type

The void data type in C is used to specify that no value is present. It does not provide a result value to its caller. It has no values and no operations. It is used to represent nothing. Void is used in multiple ways as function return type, function arguments as void, and pointers to void.

Syntax:

// function return type void
void exit(int check);
// Function without any parameter can accept void.
int print(void);
// memory allocation function which
// returns a pointer to void.
void *malloc (size_t size);

 

 

Ø Size of Data Types in C

The size of the data types in C is dependent on the size of the architecture, so we cannot define the universal size of the data types. For that, the C language provides the sizeof() operator to check the size of the data types.

Example

C

// C Program to print size of

// different data type in C

#include <stdio.h>

 

int main()

{

    int size_of_int = sizeof(int);

    int size_of_char = sizeof(char);

    int size_of_float = sizeof(float);

    int size_of_double = sizeof(double);

 

    printf("The size of int data type : %d\n", size_of_int);

    printf("The size of char data type : %d\n",

           size_of_char);

    printf("The size of float data type : %d\n",

           size_of_float);

    printf("The size of double data type : %d",

           size_of_double);

 

    return 0;

}

 

 

 

Ø  Expression: An expression is a combination of operators, constants and variables. An expression may consist of one or more operands, and zero or more operators to produce a value.

Lightbox

Example:

a+b

c

s-1/7*f

.

.

etc

Types of Expressions:

Expressions may be of the following types:

  • Constant expressions: Constant Expressions consists of only constant values. A constant value is one that doesn’t change.
    Examples:

5, 10 + 5 / 6.0, 'x’

  • Integral expressions: Integral Expressions are those which produce integer results after implementing all the automatic and explicit type conversions.
    Examples:

x, x * y, x + int( 5.0)

where x and y are integer variables.

  • Floating expressions: Float Expressions are which produce floating point results after implementing all the automatic and explicit type conversions.
    Examples:

x + y, 10.75

where x and y are floating point variables.

  • Relational expressions: Relational Expressions yield results of type bool which takes a value true or false. When arithmetic expressions are used on either side of a relational operator, they will be evaluated first and then the results compared. Relational expressions are also known as Boolean expressions.
    Examples:

x <= y, x + y > 2

  • Logical expressions: Logical Expressions combine two or more relational expressions and produces bool type results.
    Examples:

 x > y && x == 10, x == 10 || y == 5

  • Pointer expressions: Pointer Expressions produce address values.
    Examples:

&x, ptr, ptr++

where x is a variable and ptr is a pointer.

  • Bitwise expressions: Bitwise Expressions are used to manipulate data at bit level. They are basically used for testing or shifting bits.
    Examples:

x << 3

shifts three bit position to left

y >> 1

shifts one bit position to right.

Shift operators are often used for multiplication and division by powers of two.

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