- C Introduction
- C - Features
- C - Applications
- C - Preprocessor
- C - Preprocessor Directives
- C - Type Definitions
- C - Function Prototypes
- C - Header Files and Libraries
- C - Main Function
- C Program Elements
- C - Datatypes
- C - Constants
- C - Operators
- C - Assignment Operator
- C - Arithmetic Operator
- C - Relational Operator
- C - Sample Program to illustrate C relational operator
- C - Logical Operator
- C - Sample Program to demonstrate logical operators
- C - Increment and Decrement Operator
- C - Sample Program to illustrate pre increment
- C - Sample Program to illustrate post increment
- C - Bitwise Operator
- C - Sample Program to illustrate bitwise Operator
- C - Conditional Operator
- C - Comma Operator
- C - Sizeof Operator
- C - Typecast Operator
- C - Operator Precedence and Associativity
- C - Identifiers
- C - Keywords
- C Statements
- C - if-else statement
- C - else-if ladder statement
- C - Switch statement
- C - Sample Program to illustrate switch statement
- C - While Statements
- C - Sample Program to illustrate while loop
- C - do-while Statement
- C - for Statement
- C - Sample Program to illustrate for-loop
- C - Break statement
- C - Continue statement
C - Datatypes
Data Types in C
Introduction to Data Types in C
In C programming, a data type is an attribute of data that tells the compiler what kind of data the variable can hold. C offers a wide range of built-in data types, which allow programmers to declare variables that can store different types of values such as integers, floating-point numbers, characters, and more.
Categories of C Data Types
C data types are classified into the following categories:
- Basic Data Types
- Derived Data Types
- Enumeration Data Types
- Void Data Type
1. Basic Data Types
The basic data types in C are the fundamental types, including integer types, floating-point types, and character types. These data types define the type of data a variable can hold and their memory size.
Integer Data Types
Integer data types are used to store whole numbers (positive, negative, or zero) without any fractional part. The size of integer data types depends on the system's architecture (e.g., 32-bit or 64-bit). The most commonly used integer types are:
- int – Used to store standard integer values.
- short – Used to store smaller integer values. (typically 2 bytes)
- long – Used to store larger integer values. (typically 4 bytes)
- long long – Used to store even larger integer values. (typically 8 bytes)
- unsigned int – Used to store only positive integers, without any negative values.
- unsigned short – Stores smaller positive integers.
- unsigned long – Stores larger positive integers.
- unsigned long long – Stores even larger positive integers.
Example of Integer Data Types
int num = 10;
short int short_num = 100;
long int long_num = 1000000;
unsigned int u_num = 500;
Floating-Point Data Types
Floating-point data types are used to store numbers with decimal points or in scientific notation. These are often used to store real numbers (numbers with fractional parts).
- float – Used for single precision floating-point numbers. (typically 4 bytes)
- double – Used for double precision floating-point numbers. (typically 8 bytes)
- long double – Used for extended precision floating-point numbers. (typically 12 or 16 bytes)
Example of Floating-Point Data Types
float pi = 3.14;
double e = 2.718281828;
long double precision_val = 3.141592653589793;
Character Data Types
Character data types are used to store single characters. In C, characters are represented using the char keyword. A char typically takes 1 byte of memory.
- char – Used to store a single character (e.g., 'A', 'z', '1').
- unsigned char – Stores characters with positive values only (range from 0 to 255).
- signed char – Stores characters with both positive and negative values (range from -128 to 127).
Example of Character Data Types
char letter = 'A';
unsigned char u_letter = 65; // ASCII value for 'A'
signed char s_letter = -100;
2. Derived Data Types
Derived data types are types that are based on basic data types. They include arrays, pointers, structures, and unions.
Arrays
An array is a collection of similar data types stored in contiguous memory locations. Arrays can store multiple elements of the same data type.
Pointers
A pointer is a variable that stores the memory address of another variable. Pointers are used to efficiently manage memory and pass large data structures to functions.
Structures
A structure is a user-defined data type that groups different data types together. It is used to represent a record.
Unions
A union is similar to a structure, but it allows different data types to share the same memory location. It is useful when you need to store different types of data, but not at the same time.
3. Enumeration Data Types
Enumerated data types, or enum, are used to assign symbolic names to integer values, making the code more readable.
Example of Enumeration
enum day { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday };
enum day today;
today = Wednesday;
In the example above, Sunday is assigned the value 0, Monday the value 1, and so on.
4. Void Data Type
The void data type is used to specify that a function does not return a value. It can also be used for pointers to indicate that they do not point to any specific data type.
Example of Void Data Type
void displayMessage() {
printf("Hello, world!\n");
}
The displayMessage function returns nothing, which is indicated by the void return type.
Size of Data Types
The size of a data type in C can vary depending on the platform and compiler, but here are some typical sizes:
| Data Type | Size (in bytes) |
|---|---|
| char | 1 |
| int | 4 |
| float | 4 |
| double | 8 |
| long long | 8 |
Understanding data types is crucial in C programming, as they define what kind of data can be stored in a variable and how much memory is required. By using the appropriate data types, you can ensure that your program runs efficiently and correctly. Mastering data types is one of the first steps in becoming proficient in C programming.
