24 Sep C++ Data Types

Like many other programming languages, such as Java, Python, etc; Variables in C++ also store data of different types. These are classified under C++ data types.

C++ Data type includes string, int, short int, float and other types. Let’s see some data types in C++, one by one.

Built-in Data types

The following are the built-in datatypes and the datatypes, which will be used while declaring variables.

int

Data Type: int
Size: 2 bytes
Range: -32768 to 32767

Data Type: unsigned int
Size: 2 bytes
Range: 0 to 65535

Data Type: signed int
Size: 2 bytes
Range: -31768 to 32767

short int

Data Type: short int
Size: 2 bytes
Range: -31768 to 32767

Data Type: unsigned short int
Size: 2 bytes
Range: 0 to 65535

Data Type: signed short int
Size: 2 bytes
Range: -32768 to 32767

long int

Data Type: long int
Size: 4 bytes
Range: -2147483648 to 2147483647

Data Type: unsigned long int
Size: 4 bytes
Range: 0 to 4294967295

Data Type: signed long int
Size: 4 bytes
Range: -2147483648 to 2147483647

char

Data Type: char
Size: 1 byte
Range: -128 to 127

float

Data Type: float
Size: 4 bytes
Range: 3.4E-38 to 3.4E+38

double

Data Type: double
Size: 8 bytes
Range: 1.7E-308 to 1.7E+308

Data Type: long double
Size: 10 bytes
Range: 3.4E-4932 to 1.1E+4932

User-Defined Data types

The following are the user-defined data types,

Structure

The struct keyword is used to declare a structure. Structure is a collection of different datatypes. Different memory locations are allocated for all the members.

Here’s an example,

Union

Union is also a collection of different datatypes. The union keyword is used to declare a union. Common memory locations are allocated for all the members, unlike structures, which allocates different memory locations.

Let’s see the difference between Structures and Unions,

Structures Example

Here the size of p1 is 7 i.e. different memory locations allocated,

Unions Example

Here the size of p1 is 4 i.e. the maximum size, common memory locations are allocated.

Class

The user-defined datatype class is used to declare variables. Objects are class variables.

Classes are discussed in the C++ classes & objects lesson.

Enumeration

If you want to attach names to numbers, then use the enumerated data type. To add enumerated data type, use the enum keyword. You can assign values in the form of 0,1,2,3, etc.