Chapter 7 Algorithms, Psuedocode, etc Flashcards
Stages of the program development life cycle
Analysis
Design
Coding
Testing
What is Analysis (PDLC)
Analysis is a process of investigation, which leads to finding out the purpose and specifications of the program
What is Design (PDLC)
Shows how the program should be developed using the program specifications from analysis
What is Coding (PDLC)
Writing the program(s) itself and iterative testing
What is Testing (PDLC)
testing program code with the use of test data
What is abstraction - analysis
Key elements for a solution are kept and unnecessary info is discarded.
What is decomposition - analysis
A complex problem is broken down into smaller parts that can be solved easily.
Methods used for design
Structure diagram
Flowcharts
Pseudocode
What is a top-down design
aka
Constant breaking down of a computer system into a set of smaller sub-systems until each sub-system only performs 1 operation.
aka stepwise refinement
Components of a computer system (decomposition)
Inputs
Processes
Outputs
Storage
What is input - decomposition
Data used by the system that needs to be entered while the system is active
What is processes- decomposition
Tasks that need to be performed by a program using the input data and prev. stored data.
What is output - decomposition
Information that needs to be displayed or printed for the users.
What is storage - decomposition
Data that needs to be stored in files on an appropriate media for use in the future.
What is linear search
An algorithm that inspects each item in a list in turn to see if the item matches the value searched for
What is bubble sort
Makes multiple passes through a list comparing each element with the next element and swapping them, until no more passes/swaps can occur.
What is validation
Automated checks carried out to ensure that data is reasonable before it is accepted.
Types of validation
Range checks
Length checks
Type checks
Presence checks
Format checks
check digits
Range checks
Checks that the value of a number is between an upper and lower bound.
explain Length checks
syntax om
pseudocode
python
Ensures that the data entered is a specific number of characters long.
pseudo: LENGTH()
py: len()
Type checks
Checks that the data entered is of a specific type
Presence checks
Checks if data has been entered
Format checks
Checks if the characters entered follow the pre-defined pattern
Check digits
An additional digit that is added to the number to make sure the entered number is error-free.
What is verification
Makes sure that has been accurately copied/transferred from another sources and input into a computer
What is double entry
Makes users enter data twice
What is screen/visual check
Manual check that is completed by the user that enters the data.
What is a trace table
Used to record results from each step in an algorithm
What is normal data
Data that is accepted by a program
What is abnormal data
Data rejected by a program
What is extreme data
smallest/largest data value that is accepted by a program
What is boundary data
smallest/largest data value accepted by a program along with smallest/largest data value rejected by a program
What is pseudocode
Simple method of showing an algorithm. Describes what the algorithm does by using English key words that are similar to those used in high-level programming language without the strict syntax rules.
what is an algorithm
Ordered set of steps to solve a problem
what is a flowchart
a diagram that shows the steps required for a task and the order in which steps are performed.
What is a structure diagram
Shows the design of a CS in a hierarchical way, which each level giving a detailed breakdown of the system into sub systems.
What is iterative testing
modular tests are conducted, code amended, and tests repeated until the module performs as required.
How is top-down design used for large computer systems
what does this do
t several programmers can work independently to develop and test different sub-systems for the same system at the same time.
This reduces the development
and testing time.
What are the begin/end symbols called in flowcharts
shape
terminator flowchart symbols
elliptical
What is the process symbol called in flowcahrts
shape
Process flowchart symbols
rectangle
Shape of input/output
Parallelogram
Shape of decision in pseudocode
diamond
always 2 flow lines - one YES one NO
a question mark
eg
x > b ?
What does a flow line show
direction of flow
What to use for linear search in psuedocode
repeat until loop
found variable - boolean
counter - integer
What is a computer system made out of
made up of sub-systems, which are made up of further sub-systems
