Data Types in C++

C++ supports a variety of data types and you can select the appropriate types as per the need of the application. C++ supports following data types :

  • Fundamental data types
  • Derived data types
  • User defined data types

Basic or fundamental data type : Basic data types are built in data types and can be classified as follows :

Integer data type: An integer is a whole number without a decimal point. A integer requires 2 bytes of memory space. The range of interest data type is -32768 to +32767. 

C++ has following into data types :

Short int, unsigned short int, signed short int, unsigned int, signed int, long int, int, unsigned long int, signed int.

The int variable can be declared as follows : 

int x;

Char data type: The keyword “char” is short for “character” data type in C++. The char variables are used to store ASCII characters, whose integer value lies in range of -128 to +127.

The char variable can be declared as char Ch= ‘X’; where ch is character variable and X is a character content.

Float data type: The float data type is used to represent real or floating point values. They generally require 4 bytes of memory for their storage. The floating point variables can be declared as follows:

Float X;

Where X is a floating point variable. Float values can store values with 7 precision.

Void data type: The void specifies an empty set of values. This is used in following situations.

  • To specify the return type of a function which does not return any values.
  • To indicate empty argument list of a function.
  • To declare generic pointers.

Derived Data type: The various data types are:

  • Arrays
  • Pointers
  • Functions

    Arrays: An Array is a collection of related data items with similar data types and having a common name. They are used to represent a group of related data items. Elements of an array is accessed by its index number.

    Pointers: Pointer is a variable that contains the address of another variable in memory. The address is the location of the variable.

    Function: A function is self contained block of statements that perform some specific task. A function is a group of program statements into a unit and gives it a name. These can also be called sub programs.
    User defined data types: The various user defined data type are as follows:

    • Class
    • Structure
    • Union

    Class: A class is a group of objects with same attributes and common behavious. Objects of same type constitute a class  e.g. Scooter, Motor cycle, Car etc. Are all the members of same class Vehicle. Objects are variables of type class. Once a class is defined, you can create number of objects.

    Structure: A structure is a method of grouping data of different data types. A structure may contain integer elements, characters elements and floating point elements. These elements are called members. Structure is declared in C++ as follows:

    Structure employee{

    char Name[50];

    int Age;

    char Sex[5];

    float Salary;


    Union:  Union is similar to structure. A structure contains members of different data types and each member has its own memory location, where as the members with in a union all share the same storage area. The Union is used to conserve memory. Union is declared in C++ as follows:

    union employee{

    int Age;

    char Code[4];



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