Notes-for-CAIE

Table of contents

• Algorithms
  • Explain how an insertion sort puts a set of data into ascending order
  • Features that a recursive algorithm must include
  • How stack used during execution of a recursive procedure
  • What is meant by a null pointer in a linked list
• Abstract Data Types
  • Stack
  • Queue
  • Binary Tree
  • Class
  • Hash table
• PERT charts
  • What is meant by critical path in a PERT chart
• GANTT charts
  • Describe GANTT chart
• Decision tables
  • Describe the purpose of a decision table
  • Decision tables
• JSP Diagrams
  • Features of JSP diagram
• Testing
  • Methods of testing
  • Items that can include in a test plan
• Programming
  • Pseudocode hints
  • Python hints
  • Read file using Pseudocode
  • File organization
• Programming Paradigm
  • Define programming paradigm
  • programming paradigms
  • What is meant by imperative programming
• Object-oriented Programming
  • What is meant by containment
  • What is meant by inheritance
  • What is meant by polymorphism
  • Why fields are private
• Exceptions
  • What is meant by an exception
  • Situations where exception handling is required
  • The benefits of using exception handling
  • Why software may not perform as expected

Algorithms

Explain how an insertion sort puts a set of data into ascending order

w20 43 Q5 [4]

• Uses a sorted and unsorted list
• Takes first value and makes it sorted list
• Takes next value and compare with previous one,
• … to find location of next value in the sorted list
• Insert it into correct position in sorted list
• Repeat until all items are in the sorted list

Features that a recursive algorithm must include

s20 43 Q2 [2]

• General case
• Base case
• It calls itself

How stack used during execution of a recursive procedure

s15 43 Q6.b

• Before procedure call is executed current state of the registers/local variables is saved onto the stack
• When returning from a procedure call the registers/local variables are re-instated

What is meant by a null pointer in a linked list

w20 42 Q6 [1]

• End of list.

Abstract Data Types

w20 42 Q5 [4]

Stack

• Linear structure.
• LIFO.
• Uses push to add items to top of stack.
• Uses pop to remove items from t op of stack.

Queue

• Linear structure.
• FIFO.
• Can be circular.
• Uses enqueue to add item to end of queue.
• Uses dequeue to add item to end of queue.

Binary Tree

• Parent node is above, and child nodes follow.
• Each node can have up to two children.
• Has a root node.
• Can have leaf nodes.
• Can be ordered or unordered.
• Examples of ordering

Class

• A class represents an object.
• Objects are instances of classes.
• Has attributes and methods.
• Classes can be inherited.

Hash table

• Key calculated from value.
• Key represents a location.
• Description of managing collisions

PERT charts

What is meant by critical path in a PERT chart

w19 43 Q1 [1]

• The shortest time to complete the project.

GANTT charts

Describe GANTT chart

w19 43 Q1 [2]

• A table that has time across the top and activities on the left, boxes are coloured to show dependencies and find critical path.

Decision tables

Describe the purpose of a decision table

w19 43 Q1 [2]

• Way of modelling logic.
• Show all possible outputs
• … based on the inputs.
• Determine which action to take in specific condition.

Decision tables

Example questions:

s20 43 Q7

• All the blocks in the table should be filled with Y or N.

JSP Diagrams

Features of JSP diagram

s20 42 Q4 [2]

• Selection: o
• Iteration: *
• Sequence

Testing

Methods of testing

w20 43 Q2 [4]

Statement	Integration	Acceptance	Alpha	Beta
Software is tested in-house by dedicated testers	√		√	√
Software is tested by the client before it is signed off		√
Software is tested by combining previously working modules	√
Software is tested using normal, abnormal and boundary data	√	√	√	√
Software is tested by releasing it to selected customers				√

Items that can include in a test plan

w20 42 Q4 [2]

• Example test data
• Test number
• Type of test
• Test description
• Expected outcome

Programming

Pseudocode hints

• Call procedure: CALL ProcedureName()
• Index starts from 0
• Declare array typed STRING of size 100: DECLARE Name : ARRAY[0:99] OF STRING
• Assignment is <-
• Substring: MID(str, index, length)

Python hints

• Remainder operator: %
• Devision to int: //
• Random int: random.randint(min, max) (inclusive)

Read file using Pseudocode

w18 43 Q2 [8]

Filename <- "myBooks.dat"
OPENFILE Filename FOR RANDOM
RecordLocation <- Hash(ISBN)
SEEK FileName, RecordLocation
GETRECORD FileName, BookInfo
CLOSEFILE FileName

File organization

s20 42 Q8 [3]

Statement	Serial	Sequential	Random
Hashing algorithm			√
No key field	√
Collisions can occur			√
Least efficient for large data	√
Most efficient for large data			√

Programming Paradigm

Define programming paradigm

w18 43 Q1 [1]

• A programming style

programming paradigms

w18 43 Q1 [2]

Given object-oriented and tell two others.

• Procedural
• Low-level
• Object-oriented

What is meant by imperative programming

w20 42 Q4 [2]

• Writing program as a sequence of steps
• … to get a result.
• Statements in program manipulates the data.
• Example is procedural programming.

Object-oriented Programming

What is meant by containment

w20 43 Q3 [2]
s20 42 Q6 [3]

• *A class contains objects of another classes
• an example from the question
• Aggregation
• …: the contained object can exist outside its super class.
• Composition
• …: object is declared and exists within its super class

What is meant by inheritance

w20 43 Q3 [2]
w20 42 Q4 [2]

• A child class can use methods from the parent class
• XX class inherits from the class XX

What is meant by polymorphism

w20 43 Q3 [2]
w20 42 Q4 [2]

• A child class can override from the parent class
• Function XX in XX class is overridden with function XX in class XX

Why fields are private

w18 43 Q5 [2]
w20 42 Q4 [2]

• Limits access to given methods only.
• Use of set method allows for validation
• … and ensures attribute is valid.
• Ensure encapsulation.

Exceptions

What is meant by an exception

s20 43 Q1 [1]

• An unwanted event

Situations where exception handling is required

s20 43 Q1 [3]

• Division by zero
• Invalid array index
• Runtime error
• Invalid input
• Hardware error
• Stack overflow
• Memory leakage

The benefits of using exception handling

s20 43 Q1 [2]

• The program will not crash
• Result does not cause further errors
• Appropriate error message
• Improve readability
• Exceptional conditions are identified

Why software may not perform as expected

w19 43 Q3 [3]

• Logic error
• Error in design
• Runtime error
• Not adequately tested