Data Types in C++
Data Types in C++:-
Data type is used to determine what
type of value a variable or a constant can contain throughout the program.
Whenever a variable is defined in C++, the compiler allocates some memory for
that variable based on the data-type with which it is declared. Every data type
requires a different amount of memory. C++ language is rich on its data types.
The variety of data types available to allow the programmer to select the type
appropriate to the needs of the application as well as the machine. In C++
language, different variables contain different data types e.g. Roll No
contains an ‘integer’ value whereas percentage contains a 'float' value.
Data types are divided into three groups:
A.
Primary
(or Fundamental) data types.
B.
Derived
data types.
C.
User-defined
data types.
A.
Primary
(or Fundamental) data types :-
All C++ compilers supports five
fundamental data types, namely integer(int), character(char), floating
point(float), double-precision(double) and void.
Character
type:
A single character can be defined as
char data type. e.g. 'a', 'z', 'e', etc. Keyword used for character data
type is char. Characters typically requires 1 byte of memory space. A variable
declared as 'char' can store only single character e.g. Yes or No Choice
requires only 'y' or 'n' as an answer.
Integer
data types:
Integer data type is used to store numeric
values without any decimal point e.g. 7, -101, 107, etc. A variable declared as
'int' must contain whole numbers e.g. age is always in number. Keyword
used for integer data types is int. Integers typically requires 4 bytes of
memory. Data type modifiers available in C++ are signed, unsigned, short, long.
Floating
point types:
The float data type is used
to store numeric values with decimal point i.e. up to 6 precision points. In
other words, float data type is used to store real values, e.g. 3.14,
7.67 etc. Keyword used for floating point data type is float. Float variables
typically requires 4 byte of memory space. A variable declared as float must
contain decimal values e.g. percentage, price, pi, area etc.
Double-precision
type:
When
accuracy provided by float is not sufficient, the type double can
be used to define number. These are known as double precision. The double
data type represents the same data type that float represent but with
greater precision. To extend the precision, we may use long double.
Keyword used for double floating point data type is double. A double variable
typically requires 8 byte of memory space.
Boolean
Data Type:
Boolean
data type is used for storing Boolean or logical values. A Boolean variable can
store either true or false. Keyword used for Boolean data type is bool.
Wide
Character Data Type:
Wide
character data type is also a character data type but this data type has size
greater than the normal 8-bit data type. Represented by wchar_t. It is
generally 2 or 4 bytes long.
Void
type:
The void type has no value.
This is usually used to specify the type of functions. The type of a function
said to be void when it does not return any value. It is used to represent an empty
value.
B.
Derived data types:-
Data types that are derived from
fundamental data types are called derived data types. Derived data types don't
create a new data type; instead, they add some functionality to the basic data
types. Two derived data type are - Array & Pointer.
Array:
An array is a collection of variables of same type i.e. collection of
homogeneous data referred by a common name. In memory, array elements are
stored in a continuous location.
Pointer:
A pointer is a special variable that holds a memory address (location in
memory) of another variable.
Function:
Function
is group of statements together perform a particular task.
C.
User-defined
data types:-
User defined data type is used to
create new data types. The new data types formed are fundamental data types.
Different user defined data types are: class, struct, union, enum, typedef.
Class:
Class is collection of data member and member function which represent real
world object.
Struct: A
struct is a user defined data type that stores multiple values of same or
different data types under a single name. In memory, the entire structure
variable is stored in sequence.
Union: A
union is a user defined data type that stores multiple values of same or
different data types under a single name. In memory, union variables are stored
in a common memory location.

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