C# - PRIMITIVE DATATYPES

 

📘 1. What are Primitive Data Types in C#?

✅ What

Primitive data types are basic built-in types used to store simple values like numbers, characters, and true/false.

👉 Examples:

• int, double, char, bool

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✅ Why use Primitive Data Types?

• ✔ Fast and efficient
• ✔ Directly supported by CPU
• ✔ Less memory usage
• ✔ Easy to use

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❌ Why NOT (Limitations)?

• ❌ Cannot store complex data
• ❌ Fixed size (limited range)
• ❌ No advanced behavior like objects

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✅ How to Use?

// Syntax
datatype variableName = value;

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📊 2. Common Primitive Data Types in C#

Data Type	Size	Example	Description
int	4 bytes	10	Whole numbers
float	4 bytes	10.5f	Decimal numbers
double	8 bytes	10.55	Large decimals
char	2 bytes	'A'	Single character
bool	1 bit	true	True/False
byte	1 byte	255	Small numbers

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💡 3. Example Program with Comments

using System;

namespace PrimitiveDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            // Integer type (stores whole numbers)
            int age = 25;

            // Double type (stores decimal values)
            double salary = 25000.75;

            // Character type (stores single character)
            char grade = 'A';

            // Boolean type (true/false)
            bool isActive = true;

            // Float type (decimal with 'f')
            float temperature = 36.5f;

            // Display values
            Console.WriteLine("Age: " + age);
            Console.WriteLine("Salary: " + salary);
            Console.WriteLine("Grade: " + grade);
            Console.WriteLine("Active: " + isActive);
            Console.WriteLine("Temperature: " + temperature);

            Console.ReadKey();
        }
    }
}

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📦 4. Memory Storage (STACK vs HEAP)

🔹 What is Stack?

• Stores primitive data types
• Fast access
• Fixed size
• LIFO (Last In First Out)

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🔹 What is Heap?

• Stores objects and reference types
• Dynamic memory
• Managed by Garbage Collector

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⚙️ 5. How Primitive Data is Stored

👉 Primitive types (like int, bool, char) are stored in:

✅ STACK memory

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🧠 Example

int x = 10;
int y = x;

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📊 Stack Diagram

STACK MEMORY
-----------------
| y = 10        |
| x = 10        |
-----------------

👉 Explanation:

• x stores 10
• y gets a copy of 10
• Both are independent

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🔁 Value Type Behavior (Important)

int x = 10;
int y = x;

y = 20;

📊 Stack Now

STACK MEMORY
-----------------
| y = 20        |
| x = 10        |
-----------------

👉 Changing y does NOT affect x

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📦 6. Heap Example (For Understanding Difference)

class Person
{
    public string name;
}

Person p1 = new Person();
p1.name = "John";

Person p2 = p1;

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📊 Memory Diagram

STACK                HEAP
------                     ----------------
p1 ----┐                | name = John   |
          ├----------> |   Person Obj    |
p2 ----┘                 ----------------

👉 Both p1 and p2 point to same object

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🔥 Key Difference

Feature	Primitive (Value Type)	Object (Reference Type)
Memory	Stack	Heap
Storage	Direct value	Reference (address)
Copy	Value copy	Reference copy
Speed	Fast	Slower

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🎯 Real-Time Example

👉 Employee age vs Employee object

int age = 30; // stored in stack

Employee emp = new Employee(); // object in heap

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🧠 Summary Diagram

VALUE TYPE (int, bool)
----------------------
STACK → stores actual value

REFERENCE TYPE (class, object)
------------------------------
STACK → stores reference
HEAP  → stores actual object

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✅Tips

• Primitive types = Value types
• Stored in Stack
• Faster and memory efficient
• Copied by value (not reference)
• 👉 C# primitive data types are value types stored in stack memory, which hold actual values directly and provide fast and efficient data handling.

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