Types of Programming Language Flashcards
what is a paradigm
a way of looking / thinking about something
- a standard
- a certain perspective
- a set of ideas
A new paradigm in business could mean a new way of reaching customers and making money
what is a programming paradigm
a certain approach we might have to programming
Which assembly language mnemonic is used to branch if the accumulator is greater than or equal to zero?
BRP
Which assembly language command will always change the value in the program counter?
BRA
Which assembly language mnemonic is used to subtract a variable from the accumulator?
SUB
Which of these is a feature of object orientated programming languages?
Select the most appropriate answer.
Programs are structured into procedures and/or functions
Uses symbolic address as labels to reference locations of data in memory
Commands have a one-to-one relationship with machine code
Programs are structured into classes, methods and instances
Programs are structured into classes, methods and instances
What keyword should be placed before an attribute or method in pseudocode if we want to make sure it can be accessed by other objects?
PUBLIC
Which of these is a feature of a low level programming language?
Select the most appropriate answer.
Source code is easier to write
Large number of instructions
Translates to many different machine types
Source code is harder to write
Source code is harder to write
What does this line of object orientated pseudo-code do?
CLASS teacher INHERITS Person
Creates a new subclass called teacher which inherits from the person class
Which is the correct definition of ‘direct addressing’?
Select the most appropriate answer.
The operand is an address to a memory location containing an address
The address is the base address plus the value in the index register
The operand is a value to be used by the instruction
The operand is the address to use by the instruction
the operand is the address to use by the instruction
indexed addressing
modifies the address by the addition of a number held in the index register
object
an instance of class
subclass
a class that extends another class. the subclass inherits the methods and attributes of the class it extends
method
a subroutine contained within a class / object designed to perform a particular task on the data within the object
superclass
a class that has been extended by another class
attribute
a single item of data within a record or object
define low level language (2 marks)
a language which is close to machine code
one mnemonic translates to one machine code instruction
a language that is most suited to the machine architecture
state three advantages of programs written in Assembly language (3 marks)
one to one relationship with machine code
can make use of special machine-dependent instructions
e.g. in the instruction set for the chip
translated program requires less memory
code can execute more quickly
easier to optimise
can work directly on memory locations
explain inheritance
a class has all the attributes and operations/methods …
…of its superclass…
…and may also have attributes and operations/methods of its own
class
a class is a type definition
a class has attributes and methods
A product manager at ‘Better Solutions Ltd’ oversees a team of developers who program in both high-level and low-level languages.
Justify why the team may sometimes choose to write programs in either a high-level or low-level language. (6 marks)
high-level language
- easier to learn / understand code …
- programs can often be developed faster
- programs are prone to less errors / bugs
- programs are easier to debug / maintain / improve
- easier to find programmers who specialise in high-level language
- some high-level languages are specifically designed to solve certain types of problems
low-level language
- code is optimised for a specific architecture
- code can execute extremely fast
- the assembled code occupies less space in the memory than the machine code equivalent produced by a high level complier
- individual statements are able to manipulate / control specific hardware components
types of programming paradigms
object-oriented programming (OOP)
imperative programming
declarative programming
procedural programming
where do all these paradigms come from
high level language
assembly language
machine code
low-level vs high-level languages diagram
HLL OO & visual languages
HLL HL language: C, Fortran, Pascal
LLL assembly language
LLL machine language
LLL hardware
high level language
uses more human readable statements and constructs
each line of code will translate to multiple lines of machine code
uses an assembler or complier to translate into machine code
much more complex and further abstracted from machine code
assembly language
uses short codes called mnemonics e.g. ADD, R1, R2 or INP X
for each mnemonic there is one sequence of 1s and 0s
they are slightly more abstracted and easier to read / write
an assembler is used to translate from assembly language to machine code
machine code
we use 1s and 0s to represent the electrical signals within the computer
it’s the closest to what is happening on the computer which makes it the least abstract
types of high level languages
imperative
- focus is on describing how a program operates
- made up of statements that will change the programs state using sequence, selection and iteration
declarative
- focuses on WHAT the program should accomplish
examples of declarative
logic
functional
examples of imperative
object oriented
procedural
imperative high level languages
object oriented
- looking at the word as objects which have attributes and methods
example: car or plane or person
procedural
- programs are built from one or more subroutines
Procedural VS OOP features
procedural - uses sequences, selection and iteration
OOP - uses sequence, selection and iteration BUT also have inheritance, objects, classes and encapsulation
Procedural VS OOP data
procedural - data is stored in local or global variables and passed using parameters to other parts of the program
OOP - data can be private to each object, stored in attributes which are retrieved and changed through methods. this concept is encapsulation
procedural VS OOP program structure
procedural - procedures and functions
OOP - classes, methods and instances
Procedural VS OOP program logic
Procedural - program flows through calls to procedures and functions
OOP - objects are created and the objects methods are called when they are needed. Objects interact with other objects whilst the program is still running
why do we need different programming paradigms
different problems need different approaches
a 3D game for example will be better suited to OOP as the character, enemies, obstacles, backgrounds etc can be different objects
simple quizzes might be suited to procedural languages as OOP would add extra complexity
which paradigm for making a mario cart
OOP
which paradigm for creating a quiz
procedural
what paradigm for designing a website
declarative - HTML
what paradigm for querying a database
Declarative - SQL
features of procedural programming
program control and flow
pre-defined functions
- sequence
- selection
- iteration
local variables
global variables
modularity
- procedures
- functions
passing parameters
procedural programming
the language tells the computer what to do by giving step by step instructions
features of procedural languages: sequence, selection and iteration
code is created in a modular way: Procedure and functions
global variables
global variables can be seen in the whole program, every function and procedure
local variables
local variables will only be able to be seen in their function on procedure. This is called the SCOPE of the variable
passing parameters
sum (a, b)
public static int sum (int start, int end)
{
int s;
s = 0;
for (int i = start; i <= end; i++)
s += i;
return s;
}
a and b are arguments
they are passed to parameter variables
this is parameter “passing”
the parameter variables are int start and int end
a is passed into int start
b is passed into int end
assembly language - low level language
the first languages were machine code languages where the programmers entered binary combinations
very difficult to read and write
it would be easier to have readable words
lead to the development of assembly languages which use mnemonics - simple letter codes like ADD, SUB, LDA
there is a one-to-one relationship with the mnemonics and the binary instruction
the mnemonics are specific to the machines CPU e.g. Intel, ARM, AMD, Qualcomm etc. They are non portable
assembler
used to translate the assembly code into machine code
the instructions is broken up into two parts …
opcode and operand
opcode
this is the action to be performed e.g. ADD, LOAD
operand
this is the data or address for the opcode to act on e.g. it could be loading data from an address OR it could be data to add
advantages of machine code and assembly language
assembly language is quick to execute as each mnemonic maps onto one machine code
can access system features without a separate interface, which would add more time
very powerful as you are interacting directly with the machine. You’re in control without any extra features a high level language might not do
smaller programs - require less memory
disadvantages of machine code and assembly language
each code is dependant on the machine
hard to code and time consuming
bug prone as there are no debugging features
hard to understand
need good understanding of hardware
why are assembly languages used for embedded systems
have limited number of tasks
size restriction with limited resources e.g. storage and cooling
program needs to make efficient use of the processor, storage and power
assembly languages can create optimised programs and efficient
why are assembly languages used for device drivers
device drivers need to interact with peripherals
they need them to perform in a specific way
assembly languages allow for precise control of hardware
the programs run quickly and are efficient
mnemonic > instruction (alternative mnemonics accepted) (there’s 11)
ADD > Add
SUB > Subtract
STA > Store (STO)
LDA > Load (LOAD)
BRA > Branch always (BR)
BRZ > Branch if zero (BZ)
BRP > Branch if positive (BP)
INP > Input (IN, INPUT)
OUT > Output
HLT > End program (COB, END)
DAT > Data location
what are the simple letter codes used in assmebly langauge
mnemonics
what converts assembly langauge to machine code?
assembler
memory addresses
The CPU accesses addressed locations in main memory.
there are different modes locations can be addressed
modes of addressing memory
immediate
direct
indirect
indexed
immediate addressing
ADD 10 0001 1010
take the following instruction above
the 0001 would mean ADD on the instruction set
the operand part would actually mean the value NOT address
The value here in denary is
8 4 2 1
1 0 1 0
so 8+2 = 10
The actual instruction is ADD 10
The operand specifies a value. This value will be used in the operation
direct addressing
ADD 10 0001 1010
take the following instruction above
the operand part would actually mean the address of the value to use
we know 1010 = 10 as 8 + 2 is 10
we would go to the address in memory and add the value inside it
the address 1010 in RAM is 0000 1110 so we add the value
In this case it’s
128 64 32 16 8 4 2 1
0 0 0 0 1 1 1 0
so 8 + 4 + 2 = 14
the operand specifies the address of a memory location. The contents of this memory location will be used in the operation
indirect addressing
ADD 10 0001 1010
take the following instruction above
the operand specifies the address of a memory location which holds the address of another memory location. the contents of the second location will be used in the operation
we know 1010 is the 10th address in RAM and it is 0000 1110, we know the denary value of that 8 digit code is 14 so we go to address 14 and use the value there
address 14 = 1010 1001
128 64 32 16 8 4 2 1
1 0 1 0 1 0 0 1
so 128 + 32 + 8 + 1 = 169
indirect addressing - whats the point
it means we can address MORE locations
indexed addressing
COME BACK TO IT**
write psuedocode for the following class
Node
Attributes
Data (string)
Methods
getData()
setData()
Class Node{
private data;
public procedure new(string d){
data = d;
}
public void setData(string newData){
data = newData;
}
public string getData(){
return data
} }
instantiate a new object called listItem with the data “Banana”
Class Node{
private data;
public procedure new(string d){
data = d;
}
public void setData(string newData){
data = newData;
}
public string getData(){
return data
} }
listItem = new Node(“Banana”)
which address mode allows you to access more addresses in memory
Indirect: The operand specifies the address of a memorylocation which holds the address of anothermemory location. The contents of the secondlocation will be used in theoperation.
Which address mode is used for applying the same instructions over an array?
Indexed: The operand specifies the address of a memory location.The contents of the index register, which is a dedicatedregister in the CPU, will be added to the address todetermine a second address. The contents of the secondlocation will be used in the operation.
what are the two other address modes
Immediate: The operand specifies a value. This valuewill be used in the operation.
Direct: The operand specifies the address of a memorylocation. The contents of this memory locationwill be used in the operation.
inheritance with badger class
Badger
Attributes
Name: String
Age: Integer
isMale: Boolean
Colour: String
Methods
getName()
setName()
getAge()
setAge()
getGender()
setGender()
getColour()
setColour()
This is a badger class
It’s very generic and doesn’t fit
We can use Inheritance to reuse the code (the attributes and methods) from the badger class and make a more specific class for either a Honey badger or European badger or American badger.
This doesn’t affect the original badger class, just extends from it
Both the Honey Badger and European Badger inherit the attributes and methods from the Badger class. They can also add their specific attributes and methods
Badger is know as the parent class and the Honey Badger and European Badger is known as the child classes. They can still access the attributes and methods from their parent class
If you want a inherited method to do something different to the parent class, you can override it in the child class
PARENT CLASS
Public string getName(){
Return name
}
CHILD CLASS
Public string getName(){
Return ”I am +” name + “a honey badger”
}
OR
Public string getName(){
Return ”I am +” name + “a European badger”
}
If I want to use the overridden method you would write:
hBadger.getName()
If you want to use the super class method you would write:
hBadger.super.getName()
