Data Types in C++

 

Data Types in C++

In C++, data types are essential for defining variables that store different kinds of values. When a variable is declared, memory is allocated based on its data type. C++ offers a combination of primitive (built-in) data types and allows the creation of user-defined types. Here’s a detailed breakdown of the types:

1. Primitive Built-in Types:

Type	Keyword	Description
Boolean	bool	Stores true or false values.
Character	char	Stores a single character (1 byte).
Wide Character	wchar_t	Stores a larger set of characters (2 or 4 bytes).
Integer	int	Stores whole numbers.
Floating Point	float	Stores single-precision decimal numbers.
Double Precision	double	Stores double-precision decimal numbers.
Valueless	void	Used to indicate no value.

2. Type Modifiers:

Some basic types can be modified using the following type modifiers:

• signed: Ensures the data type can store both negative and positive values.
• unsigned: Restricts the data type to only store positive values, thus expanding its range.
• short: Reduces the storage size (applies to integers).
• long: Increases the storage size (applies to integers and doubles).

3. Memory Allocation and Ranges:

Data Type	Size	Range
char	1 byte	-127 to 127 (signed) or 0 to 255 (unsigned)
int	4 bytes	-2,147,483,648 to 2,147,483,647
unsigned int	4 bytes	0 to 4,294,967,295
short int	2 bytes	-32,768 to 32,767
unsigned short int	2 bytes	0 to 65,535
long int	4 bytes	-2,147,483,647 to 2,147,483,647
float	4 bytes	±3.4e±38 (~7 digits precision)
double	8 bytes	±1.7e±308 (~15 digits precision)
long double	8 bytes	Similar to double, more precision
wchar_t	2 or 4 bytes	Represents wide characters

4. Example Program to Check Data Type Sizes:

#include <iostream>

using namespace std;

int main() {

    cout << "Size of char : " << sizeof(char) << endl;

    cout << "Size of int : " << sizeof(int) << endl;

    cout << "Size of short int : " << sizeof(short int) << endl;

    cout << "Size of long int : " << sizeof(long int) << endl;

    cout << "Size of float : " << sizeof(float) << endl;

    cout << "Size of double : " << sizeof(double) << endl;

    cout << "Size of wchar_t : " << sizeof(wchar_t) << endl;

    return 0;

}

This program will output the size of various data types based on the system/compiler being used.

5. typedef Declarations:

typedef is used to create an alias for an existing type, which makes code more readable. The syntax is:

typedef existing_type new_name;

Example:

typedef int feet;

feet distance; // Equivalent to int distance;

6. Enumerated Types:

An enumeration allows the definition of a set of named integer constants. Enumerated types are defined using the enum keyword:

enum color { red, green, blue };

color c = blue;  // Assigning enumerated value to variable

By default, the first enumerator is assigned 0, the second 1, and so on.

You can assign custom values to the enumerators:

enum color { red, green = 5, blue };  // green = 5, blue = 6

Summary:

C++ offers a diverse range of data types that provide flexibility in storing various types of information. The use of built-in types along with modifiers allows programmers to effectively manage memory while ensuring proper data storage. Data types like enum and typedef further enhance readability and make code easier to maintain.