Introduction to Fundamental Data Types in C++.

Understanding data types in C++ is like learning the alphabet before writing words. These are the core building blocks that determine the kind of data a program can store and operate on—such as numbers, characters, or logical values.

Variables: The Building Blocks

A variable is a named storage location capable of holding data. Before delving into the specifics of data types, let's first grasp the concept of variables.

int age; // declares an integer variable name "age"

Here, int is a data type indicating that the variable age will store integer values. C++ offers a variety of fundamental data types to cater to different types of information.

Categories of Fundamental Data Types

1️⃣Integer Types

int:

• Stores whole number
• Typically 4 bytes (on 32/64-bit systems)
• Range: approximately -2147483648 to 2147483647.

int number = 7;

short, long, long long:

These are variations of the int type, occupying less or more memory, respectively. Their usage depends on the range of values you anticipate for a variable.

short s = 100;      // Usually 2 bytes
long l = 100000L;   // Usually 4 or 8 bytes
long long ll = 1e18;// At least 8 bytes

2️⃣Floating-Pont Types

These are used for representing real numbers.

float:

• Single precision (4 bytes)
• Approx. 6 decimal digits of precision

doble:

• Double precision (8 bytes)
• Approx. 15 decimal digits of precision

float pi = 3.14;
double gravity = 9.81;

3️⃣Character Types

char:

• Stores a single ASCII character
• Occupies 1 byte
• Also usable for small integer values (0-255)

char grade = 'A';

4️⃣Boolean Type

bool:

• Stores only true or false
• Introduced in C++ (not present in C)
• Internally stored as 1 byte

bool isHot = true;

5️⃣Void Type

void (No type):

The `void data type id special because it is used to indicate that a function does not return any value. It is typically used in the function declaration to signify that the function performs a tasks but doesn't produce a result. Void represents the absence of a type.

• Represents “nothing” or “no value”.

void greetUser() {
    cout << "Hello, User!" << endl;
}

In this example, the greetUser function has a void return type, indicating that it doesn't return any value.

void*:

Additionally, the void type is commonly used in the context of pointers. A void pointer, also known as a generic pointer, is a pointer that can point to objects of any data type. This flexibility makes it a powerful tool when dealing with memory allocation and manipulation.

void* genericPointer;

int integerValue = 10;
genericPointer = &integerValue;

double doubleValue = 3.14;
genericPointer = &doubleValue;

⚠️ Must be cast back to a specific type before dereferencing.

Understanding Size and Range

It's crucial to be mindful of the size and range of each data type especially when dealing with memory constraints or the potential for overflow. The sizeof() operator can be employed to determine the size of a variable in bytes.

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