What is a Data Type?

🎙️ Introduction

Hello everyone!

Welcome to this important chapter — What is a Data Type?

In the previous lesson, we understood what data is and why it is important in programming. Now the next big question is:

👉 How does a computer know what type of data it is storing?

If we store the number 10, the computer must know whether...Read More

🔹 Step 1: Basic Meaning of Data Type

A data type is a classification that tells the computer what kind of data is being stored.

In simple words:

👉 A data type defines the type of value a variable can hold.

It tells the compiler three very important things:

What kind of data is stored

How much memory to allocate

What operations can be performed

Without data types, the computer would not know how to...Read More

🔹 Step 2: Why Do We Need Data Types?

Imagine you have different containers in your kitchen:

A bottle for water

A jar for sugar

A box for rice

Each container is designed for a specific type of item.

Similarly, in programming:

An integer data type stores whole numbers...Read More

🔹 Step 3: Memory Allocation and Data Types

Every data type occupies a specific amount of memory.

For example (in most systems):

int → 4 bytes

float → 4 bytes

double → 8 bytes

char → 1 byte

When we declare a variable, the compiler checks the data...Read More

🔹 Step 4: Types of Data Types in C

In C language, data types are generally classified into:

1️⃣ Basic (Primary) Data Types
2️⃣ Derived Data Types
3️⃣ User-Defined Data Types

Let us understand each category clearly.

🔸 Basic (Primary) Data Types

These are the fundamental data types provided by C.

They include:

int → for integers

float → for decimal numbers

double → for larger decimal numbers

char → for single characters

These are the most commonly used data types...Read More

🔸 Derived Data Types

These are formed from basic data types.

Examples include:

Arrays

Pointers

Functions

They are called derived because they are derived from...Read More

🔸 User-Defined Data Types

These are created by programmers.

Examples:

struct

union

enum

typedef

They allow programmers to create their own...Read More

🔹 Step 5: Operations Based on Data Types

Data types also determine what operations can be performed.

For example:

If we have two integers:
We can add, subtract, multiply, and divide them.

If we have characters:
We cannot directly perform arithmetic operations like...Read More

🔹 Step 6: Type Safety and Error Prevention

Data types help prevent errors.

For example:

If we try to store a decimal value inside an integer variable:
The decimal part may be lost.

If we try to store a large number in a small data type...Read More

🔹 Step 7: Real-Life Example

Let’s take a student record system.

We need to store:

Student ID → integer

Name → string

Grade → character

Percentage → float

If we mix these data types incorrectly, the system will...Read More

🔹 Step 8: Data Types and Program Efficiency

Choosing the correct data type improves:

Memory efficiency

Program speed

Performance

For example:

If we use double when float is enough, we waste memory.

If we use int when char is enough, we use more memory...Read More

🔹 Step 9: How Data Types Connect to Variables

Data types are always used with variables.

Example:

We cannot simply write:
age = 20;

We must first define its data type:
int age;

This tells the compiler that age will store an integer...Read More

🔹 Step 10: Why Understanding Data Types is Important

Data types are the foundation of programming.

Without them:

Memory cannot be managed properly.

Calculations cannot be performed correctly.

Programs may crash or behave unexpectedly.

Understanding data types makes it easier to:

Work with variables Perform operations

Manage memory Build efficient programs...Read More

📌 Summary

In this chapter, we learned:

A data type defines the type of data a variable can store.

It determines memory allocation and allowed operations.

C has basic, derived, and user-defined data types...Read More