Types of programming languages

Question 1

what is a programming paradigm?

Answer 1

It is a style of programming
Some languages only support one type of paradigm (eg. Haskell, small Basic) but some support more than one (eg. Python, Java, C#)

Question 2

What are the 4 programming paradigms? (and give an example)

Answer 2

• procedural programming - eg. Python, Basic, C#
• object oriented - eg. Python, Java, VisualBasic.NET
• declarative programming - eg. SQL, Prolog
• Functional programming - eg. Haskell, Javascript, Logo

Question 3

what is procedural programming?

Answer 3

• consists of a series of instructions that tell the computer what to do with the inputs in what order to solve the problem
• languages using this paradigm have built in data types (eg. integer, floating point numbers etc) + data structures such as arrays + records
• programmers can also define their own abstract data types eg. queue, stack, tree, hash table, etc

Question 4

what is structured programming?

Answer 4

• a type of procedural programming
• uses sequence, selection, iteration + recursion instead of goto techniques
• uses modular techniques - splits large programs into manageable chuncks

Question 5

what is declarative programming?

Answer 5

• you write statements that describe the problem to be solved
• language implementation decided the best way to solve the problem
• doesnt execute in the same order as the statements

Question 6

what is logic programming?

Answer 6

• a form of declarative programming
• a paradigm that expresses the logic of a computation without expressing its control flow
• programs consist of logical statements
• eg. prolog

Question 7

what is functional programming?

Answer 7

• functions are used as the building blocks of a program
• statements are written as a series of functions which accept input data as arguments + return an output

Question 8

when might a declarative programming language be used?

Answer 8

• in expert systems (eg. medecine)
• embodies fasts and rules about a particular field of knowledge - medical diagnosis, oil exploration, tax regs
• natural language processing (normal human language) - text to speech, spell checking

Question 9

what is backtracking?

Answer 9

• usually done during recursion
• if a dead end is found go back to the previous choice that was made
• this is repeated until the thing needed is found/all possible paths are exhausted

Question 10

what is an abstract data type?

Answer 10

queue, stack, tree, graph, hash table, etc.

Question 11

what is object oriented programming?

Answer 11

• more abstract thinking - think about the objects that will complete the tasks, not the data structures + algorithms
• makes it possible to abstract details of implementation away from the programmer
• makes reusable code
• programs are easy to maintain
• programs are made of objects with attributes (data about the object) + methods (operations on the data)

Question 12

what is a class?

Answer 12

the description of what the data looks like (the state) and what the data can do (the behavior) - kinda like a blueprint for the object- defines attributes + methods

Question 13

what is an object?

Answer 13

a specific instance created based on the blueprint (class) that has its own unique data values

Question 14

what is instantiation?

Answer 14

the process of creating an object of a class - memory is allocated for its attributes + initial values are set

Question 15

what is a constructor?

Answer 15

a method that creates an instance of a class. in pseudocode:
instance = new class(parameters)

Question 16

what does it mean if an attribute is private?

Answer 16

users cannot directly access or change them - they can only be changed through methods (functions or procedures)

Question 17

what is recursion?

Answer 17

• it is a programming construct where a subroutine call itself during execution until the stopping condition is met
• produces the same results as iteration but using fewer lines of code
• can be inefficient with memory and cause a stack overflow (the stack runs out of memory)
• difficult to trace, esp with more function calls

Question 18

what are local variables and why are they good?

Answer 18

• variables that can be accessed only within the block of code in which they were defined
• eg. if defined in a subroutine can only be accessed in the subroutine
• good because it makes sure subroutines are self contained - variables can’t be affected by code elsewhere

Question 19

what is a global variable and why are they good?

Answer 19

• variables that can be accessed across the whole program
• any variables declared in the main body of the program are global variables
• useful if a value needs to be used in multiple parts of the program
• not great because they can be accidentally overwritten
• also use more memory than local variables because they are terminated at the end of the program rather than the end of the subroutine

Question 20

what is encapsulation?

Answer 20

when attributes and methods are bundled together under a single unit - eg. a class
good because it protects attributes being accessed directly
code for different classes can be produced independently of each other

Question 21

what is a setter?

Answer 21

a method that sets the value of a particular attribute

Question 22

what is a getter?

Answer 22

a method that retrieves the value of a given attribute

Question 23

what is the difference between a function and a procedure?

Answer 23

• function: returns a value
• procedure: doesnt return a value, just completes a task

Question 24

what is inheritance?

Answer 24

• a relationship among classes where a subclass shares all the attributes + methods from a parent class/superclass
• good because it saves time redefining shared attributes + methods

Question 25

what does a class diagram look like?

Answer 25

there are boxes representing the classes, with their attributes and methods and arrows pointing from subclasses to superclasses

Question 26

what is polymorphism?

Answer 26

a programming language's ability to process objects differently depending om their class - methods are redefined this can lead to the same method producing different outputs depending on the object involved

Question 27

what is overriding?

Answer 27

redefining a method in a subclass + altering code so that it functions differently + produces a different output

Question 28

what is overloading?

Answer 28

passing different parameters into a method to produce a different output

Question 29

what are the advantages of object oriented programming?

Answer 29

- forces an extensive planning phase - better designs with fewer weaknesses - encapsulation means that different object's code can remain independent of each other + be tested separately - once an object is created you don't need to know how its methods work to use them - new objects can be easily created with small differences to existing ones - reuseable - defined and tested objects can be used in different programs - good framework for code libraries - lots of software components that can be easily adapted by a programmer - easier to maintain than a procedural language program because of modular structure

Question 30

what do mnemonics in assembly language represent?

Answer 30

they represent operation codes + addresses