C Data Types | C Programming

Data types tell the compiler what kind of data a variable will store and how much memory it needs.

They help the compiler allocate memory correctly and perform operations safely.

EASY LEVEL (Beginner Friendly)

Why Data Types Are Needed

Different data needs different memory
Numbers, characters, and decimals are stored differently
Data types avoid confusion and errors

Main Types of Data Types in C (Easy)

1. Integer Type (`int`)

Used to store whole numbers.

int age = 20;

Examples: -5, 0, 100

2. Character Type (`char`)

Used to store single characters.

char grade = 'A';

Stores only one character at a time.

3. Floating Point Type (`float`)

Used to store decimal numbers.

float price = 99.50;

4. Double Type (`double`)

Used to store large decimal values with more accuracy.

double distance = 12345.6789;

5. Void Type (`void`)

Used when no value is returned.

void show() {
}

EXPERT LEVEL (Technical & Exam-Oriented)

Classification of Data Types in C

1. Basic (Primitive) Data Types

Type	Description
`int`	Integer values
`char`	Character data
`float`	Decimal numbers
`double`	High-precision decimals
`void`	No value

2. Derived Data Types

Derived from basic types.

Type	Example
Array	`int a[5];`
Pointer	`int *p;`
Function	`int add();`

3. User-Defined Data Types

Created by the programmer.

Type	Purpose
`struct`	Group different data types
`union`	Share memory
`enum`	Named constants
`typedef`	Rename data types

Memory Size (Typical)

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

(Note: Size may vary by system/compiler)

Example Showing Data Types in Use

int count = 10;
char letter = 'C';
float marks = 85.5;
double avg = 92.3456;

Each variable:

Has a type
Uses specific memory
Supports type-specific operations

Key Expert Insights

Data types define memory allocation
They ensure type safety
Correct data type choice improves performance
Wrong data type can cause overflow or precision loss

One-Line Exam Answer

Data types in C specify the type of data a variable can store and determine the amount of memory allocated for it.

Data Types in C