Section 1
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Dynamic Scope
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Date created
Mar 1, 2020
Cards (67)
Section 1
(50 cards)
Dynamic Scope
Refers to scope of a variable that is defined at run-time. It refers to the identifier with the most recent environment
Explicit Heap Dynamic Variable
A nameless/abstract variable that is allocated/deallocated with an explicit allocation operator. Ex: bsh % set = new HashSet();
int[] a = new int[10];
Create an array in Java
Pointer
An object that stores the memory address of another value located in memory. Can be re-assigned any number of times Can be assigned NULL directly
Static Variable
Variable declared with a keyword Lasts program's entire run-time May not always be visible to functions/subunits in the program
Float
A single precision (32 bit) floating point data type
Ordinal
A data type who's values can be counted. A finite, ordered set of values (Types: integer, char) Ex: x = 1..10; y = 'a'..'z'; Advantages: Readability, reliability
Dereference Operator
Operator (symbol: *) that returns a value equivalent to the value at the pointer address Ex: int x; int *p; x = 0; p = &x; //this sets p equal to the value at x's memory location *p = 1; //this sets the value of x's (also p's) memory location to 1 print x; output: 1
Rectangular Array (2D Array)
A 2D array with a number of rows, and columns. Each row, and column has the same number of objects
Local Variable
A variable declared in the same program/function in which it is used, and is not available to other subunits/functions in the program
Address Operator
Operator (symbol: &) that returns the memory address of a variable.
Implicit Heap Dynamic Variable
A variable that is allocated without the use of an explicit allocation operator. Ex: list = [10.2, 3.5] This variable storing [10.2, 3.5], not the variable "list"
Stack Dynamic Variable
A variable (local by default) that is bound/unbound to an address on the stack at run-time
Nonlocal Variable
A variable not declared in the same program subunit in which it is used, and is not available to every subunit/function in the program
Reference Environment
Collection of variables that are visible that can be used by certain statements in a program (Similar to scope)
R Value
The value of a variable
Associative Array
An abstract array type that can hold data in "key, value" pairs. Ex: A list of phone numbers where you can look up a person's name by finding their phone number. The name is the value and the number is the key
Static Binding
Variables are bound to a type at compile-time. Type cannot be changed after execution. pros: flexibility cons: high memory cost, and type error
C++, Java, C#
In the languages __________ , variable declarations can appear anywhere statements can appear
case sensative
Syntax in C-based languages are __________
Keywords
__________ are special only in certain context
Column Major (Order)
Method for storing multidimensional array where consecutive elements of a column reside next to each other Starts on the first column, then the second column, etc
Runtime Heap
A large storage area that is managed at run-time used to store data in some variable amount
int a[10];
Create an array in C++
Struct
A collection of variables of different data types that are referred to by a common name. A separate memory location is allotted to each member of the structure Minimum of 8 bytes
1D Array
An array where the values are stored in the form of a list. Ex: int[ ] a = {11, 22, 33, 44, 55};
Static Scope
Refers to the scope of variable that is defined at compile-time. It is always refers to the variable with top level environment
Alias
Two variables referring to the same memory location (harmful to readability)
Jagged Array (3D Array)
A 3D array of arrays in which the sub-arrays can be different sizes. Each row, and column can have a different number of objects
L Value
The address of a variable
Reference
An object that stores the memory address of another value located in memory. Cannot be re-assigned Cannot be assigned NULL directly
names
Variables do not need __________
Global Variable
A variable not declared in the same program subunit in which it is used (lasts program's entire run-time), and is available to every function/subunit in the program
Dangling Pointer
Pointers that do not point to a valid object of the appropriate type. Caused by deleting or deallocating without modifying the value of the pointer. Ex: int *aptr = new int(5); int *bptr = aptr; aptr = bptr; delete bptr; now bptr is dangling
Scope
The visibility of variables (Which parts of a program can use a variable)
Slice
An operation that extracts a subset of elements from an array and packages them as another array. Ex: a[1:3]
Dynamic Binding
Variables are bound to a type at run-time depending on the value assigned, and can be changed after execution
Array Access
Access function for single-dimensional arrays
Row Major (Order)
Method for storing multidimensional array where consecutive elements of a row reside next to each other Starts on the first row, then the second row, etc
Memory Leak
A state in which a program requests memory but never releases it, which can eventually prevent other programs from running. Caused an object stored in memory is not accessible by the running code. Ex: int *aptr = new int(5); int *bptr = new int(6); aptr = bptr; Heap storage of int 5 is no longer accessible
Double
A 32 bit floating point data type
Primitive Data Type
The most basic data types available: boolean , byte , char , short , int , long , float and double
Record
Aggregate of data & elements where individual elements are defined by name
Block Scope
The area within if, switch conditions or for and while loops.
Multidimensional Array
An array of arrays whose elements are stored in row-major order. Ex: int[ ][ ] a = { { 1, 2 }, { 3, 4, 5 } };
Call Stack (Runtime Stack)
A data structure that stores information about the active subroutines of a computer program. It is used at runtime when methods are invoked, holds "call frame" containing local variables, parameters, etc...
Common int Types
Byte, short, int, and long
Storage Binding
Allocation: getting a cell from some pool of available cells Deallocation: putting a cell back into the pool
Union
A collection of variables of different data types that are referred to by a common name. A single memory location is allotted to all members of the structure Minimum of 4 bytes
Reserved words
__________ can't be used as variable names. They vary in different languages
Section 2
(17 cards)