What are Data Types?
Data types in C specify the type of data that a variable can hold. They define the size and layout of the variable’s memory, the range of values that can be stored, and the operations that can be performed on them. C provides several built-in data types, and programmers can also define their own custom data types using structures and typedefs.
Built-in Data Types in C:
- Integer Types:
- int: Basic integer type, typically representing a 32-bit signed integer.
- char: Character type, usually representing a single ASCII character.
- short: Short integer, typically smaller than int.
- long: Long integer, typically larger than int.
- long long: Extended precision integer.
- Floating-Point Types:
- float: Single-precision floating-point number.
- double: Double-precision floating-point number.
- long double: Extended-precision floating-point number.
- Void Type:
- void: Denotes the absence of type. Used in function declarations to indicate that the function does not return a value.
- Derived Types:
- Arrays: Collection of elements of the same data type.
- Structures: User-defined data type that groups related data items.
- Pointers: Variables that store memory addresses.
Size and Range of Data Types:
The size of data types may vary depending on the compiler and the platform. However, C standard specifies minimum ranges for each data type:
- int: At least 16 bits, typically 32 bits.
- char: At least 8 bits, usually represents ASCII characters.
- short: At least 16 bits.
- long: At least 32 bits.
- long long: At least 64 bits.
- float: Single-precision, typically 32 bits.
- double: Double-precision, typically 64 bits.
- long double: Extended-precision, varies depending on the platform.
Modifiers:
C provides type modifiers to extend the range or precision of basic data types:
- signed: Indicates that a data type can represent both positive and negative numbers (default for int).
- unsigned: Indicates that a data type can represent only non-negative numbers.
- short, long, long long: These modifiers can be combined with integer types to specify the size more precisely.
Typedef:
C allows programmers to create custom data types using typedef. It provides an alias for existing data types, making the code more readable and manageable.
typedef int myInt; // Creates an alias ‘myInt’ for ‘int’ typedef struct { int age; char name[20]; } Person; // Defines a custom data type ‘Person’
Enumerated Types:
Enumerated types (enum) allow programmers to create named constants representing integer values.
enum Day {Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday};
Conclusion:
Understanding data types in C is crucial for writing efficient and correct programs. Programmers need to choose appropriate data types based on the requirements of their applications to ensure optimal memory usage and computational efficiency.