Data Types

Data types in C++ define the type of data a variable can store. They help the compiler understand how much memory to allocate and what kind of operations can be performed on the data.

What are Data Types?

A data type specifies:

• The kind of value a variable can hold
• The size of memory required
• The operations allowed on that data

Example:

int age = 18;

Here, int is the data type.

Types of Data Types in C++

C++ data types are mainly divided into:

• Basic (Primitive) Data Types
• Derived Data Types
• User-Defined Data Types

Basic Data Types

int

Used to store whole numbers.

int number = 10;

float

Used to store decimal values.

float price = 99.5;

double

Used to store large decimal numbers with more precision.

double value = 123.456789;

char

Used to store a single character.

char grade = 'A';

bool

Used to store true or false values.

bool isPassed = true;

string

Used to store text.

string name = "Ali";

Example Program

#include <iostream>
using namespace std;

int main() {
    int age = 18;
    float marks = 85.5;
    char grade = 'A';
    bool passed = true;

    cout << age << endl;
    cout << marks << endl;
    cout << grade << endl;
    cout << passed << endl;

    return 0;
}

Output

18
85.5
A
1

Derived Data Types

Derived data types are created from basic data types.

Examples:

• Arrays
• Pointers
• Functions

Example:

int numbers[5];

User-Defined Data Types

These are created by the programmer.

Examples:

• Structures
• Classes
• Enumerations

Example:

struct Student {
    string name;
    int age;
};

Size of Common Data Types

Data Type	Typical Size
int	4 bytes
float	4 bytes
double	8 bytes
char	1 byte
bool	1 byte

Why Data Types are Important

Data types are important because they:

• Define memory usage
• Improve program efficiency
• Prevent invalid operations
• Help organize data correctly

Real-Life Example

• int → Number of students
• float → Product price
• char → Grade letter
• bool → Pass or fail status
• string → Person name

Conclusion

Data types are a fundamental part of C++ programming. They define what kind of data can be stored and processed in a program. Understanding data types helps write efficient, accurate, and organized code.