Primitive Data Types in Programming

Study Notes

Primitive Data Types

A data type defines a collection of values and operations on those values.
Primitive data types are not built from other types.
Common primitive data types include numeric, Boolean, and character types.
Numeric Types:
- Integer: Most widely used numeric data type.
- Floating-point: Represents real numbers, approximations of many values.
- Decimal: Fixed decimal digits with a set position for the decimal point.
Boolean Type: Limited to two values: true and false.
Character Type: Stores a single character, includes letters, digits, punctuation, and whitespace.

Character String Types

A character string (or string) type represents sequences of characters.
Common operations include assignment, concatenation, substring reference, comparison, and pattern matching.
String Length Types:
- Static: Fixed length determined when created.
- Limited dynamic: Varies up to a defined maximum.
- Dynamic: Varies with no maximum limit.

User-Defined Ordinal Types

Ordinal types consist of a range of values associated with positive integers.
Enumeration Type: Lists all possible named constants.
Subrange Type: Represents a subset of values from another ordinal type.

Structured Data Types

Array: Stores a fixed number of a single type; accessed via subscripts or indexes.
Array Types:
- Static array: Statically bound subscripts, static storage allocation.
- Fixed stack-dynamic: Statically bound subscripts, allocation at execution time.
- Stack-dynamic: Dynamically bound subscripts and storage allocation.
- Fixed-heap dynamic: Fixed storage post-allocation, with variable subscript ranges.
- Heap-dynamic: Both subscript ranges and storage allocation are dynamically bound.
Common array operations: Assignment, concatenation, equality/inequality comparison, slices.
Rectangular Array: Multidimensional array with equal elements in rows and columns.
Jagged Array: Contains rows with varying numbers of elements.
Slice: A new array produced by extracting elements from another array.
Associative Array: Unordered collection indexed by keys.
Record: Collection of data elements identified by names.
Tuple: Similar to a record but elements are unnamed.
List: Ordered sequence of values, usually without punctuation.
Union: Allows storage of different types at different times, can be free or discriminated (with a type indicator).

Pointer and Reference Types

Pointer Type: Contains memory addresses; includes a nil value for invalid addresses.
Nil indicates that a pointer cannot reference a memory cell.
Pointers allow access to dynamically allocated memory (heap).
Heap-Dynamic Variables: Variables stored in the heap.
Anonymous Variables: Variables without assigned names.
Key pointer operations:
- Assignment: Sets a pointer to an address.
- Dereferencing: Accesses the value at a pointer's address.
Reference Type: Refers to objects or values in memory.

Other Concepts

Type Checking: Ensures operand types are compatible.
Coercion: Automatic conversion of operand types.
Type Error: Inappropriate application of an operator to an operand.
Dynamic Type Checking: Type checking performed at runtime.
Strongly Typed Language: Always detects type errors.
Type Equivalence: Two types are equivalent if substituting one for the other doesn't require coercion.
Type Equivalence Approaches: Name type equivalence and structure type equivalence.

Description

This quiz covers the basics of primitive data types in programming, including numeric, Boolean, and character types. Learn about integer and floating-point data types and how they are used in imperative languages.