Data Types in C

In C programming, data types define the kind of data a variable can hold. They specify how much memory to allocate and how to interpret the data stored in that memory. Understanding data types is essential for effective programming in C.

1. Basic Data Types

C has several built-in data types that can be classified into the following categories:

a. Integer Types

Integer types are used to store whole numbers. The sizes of integer types can vary based on the system architecture, but the following are commonly used:

Example:

int age = 25;          // Integer
short count = 100;    // Short Integer
long population = 1000000; // Long Integer
long long distance = 1234567890123; // Long Long Integer

b. Floating Point Types

Floating point types are used to store numbers with decimal points. The common floating-point types are:

Example:

float temperature = 36.6;    // Single Precision
double pi = 3.141592653589793; // Double Precision
long double preciseValue = 1.234567890123456789; // Long Double

c. Character Type

The character type is used to store single characters.

Example:

char letter = 'A'; // Character

2. Derived Data Types

C also supports derived data types, which are built from the basic data types.

a. Arrays

An array is a collection of elements of the same data type, with a fixed size.

Example:

int numbers[5] = {1, 2, 3, 4, 5}; // Array of integers
char letters[4] = {'A', 'B', 'C', 'D'}; // Array of characters

b. Structures

A structure is a user-defined data type that groups variables of different types under a single name.

Example:

struct Student {
    char name[50];
    int age;
    float grade;
};
 
struct Student student1 = {"John Doe", 20, 88.5};

c. Unions

A union is similar to a structure, but it allows storing different data types in the same memory location. Only one member can contain a value at any given time.

Example:

union Data {
    int intValue;
    float floatValue;
    char charValue;
};
 
union Data data;
data.intValue = 5; // Only this member can hold a value at a time

d. Pointers

A pointer is a variable that stores the memory address of another variable.

Example:

int num = 10;
int *ptr = # // Pointer to an integer

3. Enumeration Types

Enumeration (enum) is a user-defined data type that consists of integral constants. It helps to define variables that can hold a set of predefined constants.

Example:

enum Color {
    RED,
    GREEN,
    BLUE
};
 
enum Color favoriteColor = GREEN; // favoriteColor can take values RED, GREEN, or BLUE

Summary

Understanding data types in C is crucial for:

• Memory management: Allocating the right amount of memory.
• Data manipulation: Knowing how to handle different types of data.

Diagram of Data Types in C