📚 Glossary
This glossary contains short explanations of key programming terms used across the site. Click a term to see the full explanation, examples, and diagrams.
C
- Casting
Manually converting a value from one data type to another.
D
- Data Type
Specifies the kind of data a variable can hold, such as integer, floating-point, or text.
- Declaration
The act of defining a variable's name and type without assigning a value.
H
- Heap
A region of memory used for storing objects and class instances, managed by the garbage collector.
I
- Identifier
The name given to a variable, method, class, or other element in code.
- Immutable
An object whose state cannot be changed after it is created.
- Initialisation
Assigning an initial value to a variable at the time of declaration or later.
K
- Keyword
A reserved word that has a predefined meaning in the language syntax and cannot be used as an identifier
M
- Mutable
An object whose state can be changed after creation.
N
- Narrowing
A type of casting that converts from a larger data type to a smaller one, potentially losing data.
O
- Overflow
When a value exceeds the maximum or minimum limit of its data type, causing it to wrap around.
P
- Primitive Type
A basic data type built into the language, such as int, float, or char.
R
- Reference Type
A data type that stores a reference to an object in memory, rather than the object itself.
S
- Stack
A region of memory that stores method calls and primitive variables, managed in a last-in-first-out manner.
T
- Two’s Complement
A binary representation for signed integers where the MSB indicates sign.
- Type
A category of data that determines the possible values and operations for a variable.
- Type Promotion
The automatic conversion of a smaller data type into a larger compatible type.
V
- Variable
A named storage location in memory for data, which has a type.
W
- Widening
Another term for type promotion, converting to a larger type without loss of data.