PAPER 2 - Algorithms, Programming, Logic Flashcards
What is analysis
- abstraction, decomposition of the problem, identification of the problem
What are the 4 main stages in the program development life cycle:
-ANALYSIS
- DESIGN
- CODING
- TESTING
What is design
- decomposition, structure diagrams, flow charts, pseudocode
What is coding
Writing program code + iterative testing
what is testing
Testing program code with use of test data
What is abstraction
- involves identifying the key parts of the problem
-
removing any unnecessary detail to make it easier to
solve
What is the purpose of structure diagrams
- show structure of the problem, its subsections + links to other subsections
What is decomposition
The breaking down of a complex problem into smaller, manageable parts which are easier to solve
What are the 4 steps of decomposition
- identify the main problem
- identify the component part of input, processes, outputs and storage
- list main sub-problems, sub-systems , functions or tasks
- break these down into smaller sub- problems or sub-tasks , which can be completed separately
In flow charts what is the symbol for input/output
Parallelogram
Flow chart symbol for process
Rectangle
Flow chart symbol for decision
Diamond
Flow chart symbol for terminator
Oval
What are the 5 data types
- integer
- real/float
- Boolean
- char
- string
What is a real/float
number with a decimal point
What is a Boolean
Either TRUE or FALSE
What is a char
A single alphabetic or numeric character
E.g. A,#, @, 6, !
What is a string
A sequence of one or more characterS
E.g. “yes”, “Hi John”
Explain the difference between a variable and a constant.
- Variable – a storage container in memory that can hold information as a number, a person’s name or a whole sentence.
-
Constant – a variable, once defined , it cannot be changed during execution of program, You cannot declare a value as a constant in python.
E.g. Value that never, or rarely changed : pi, speed of light
Pi = 3.142
Radius = float(input(“Enter radius”)
Circle_area = pi*(radius^2)
Print(Circle_area)
What is a variable and what is a constant
Variable = radius
Constant = Pi
What is the assign symbol operator un psuedocode
<—
WHILE….__
DO
A <— 22 MOD 5
What is A?
2 (reminder)
C <— 22 DIV 5
C = 4
What is a sequence
two or more statements written and executed one after the other in sequence
What is a selection statement
Selection stemmet comprises an IFor CASE stement and a logical expression.
IF is what kind of statement
Selection statement
What are the 3 iterations:
- FOR … NEXT
- WHILE … ENDWHILE
- REPEAT … UNTIL
What is a nested if statement
An IF statement inside another IF statement :
IF .. THEN
ELSE IF … THEN
ELSE
ENDIF
What is a CASE statement
CASE statement - allow one of several branches of code to be executes, depending on the value of a variabel
Think of a CASE programme about member types
INPUT MemberType
CASE OF MemberType
“Junior” :EntryFee <—2.0
“Senior” :EntryFee <— 3.0
“Special” : EntryFee <— 0.0
OTHERWISE OUTPUT “Invalid member type” //Other conditions not net
ENDCASE
CASE …. ___________
OTHERWISE
Name a count-controlled loop
FOR … NEXT
Counter -
A counter is automatically incremented each time the loop is performed
A code to print out numbers from 1 - 10
FOR Count <— 1 TO 10
OUPUT COUNT
NEXT Count
Code to print out numbers 2,5,8
FOR i <— 2 TO 10 STEP 3
OUPUT i
NEXT i
Example of a pre-conditioned loop
WHILE…DO….ENDWHILE
What are pre-conditioned loops
Controlled by a Boolean condition white is checked before the loop is entered
What are post-conditioned loops
Controlled by a Boolean condition white is checked at the end the loop is entered. therefore performed at least once
Example of a post-conditioned loop
REPEAT….UNTIL
Write a pseudocode algorithm which allows a user to input numeric scores and prints how many of them are over 100. The program allows the user to enter any number of scores. If the user enters “-1” the program will end.
Count <- 0
Score <- 0
WHILE score<> -1 DO
OUPUT “Enter Score”
INPUT score
IF score > 100
THEN
Count = Count+1
ELSE
ENDIF
ENDWHILE
OUPUT Count
What are the 4 string operations:
- LENGTH ( )
- LCASE ( )
- UCASE ( )
- SUBSTRING ( str, start, length)
What does LENGTH ( ) do?
Output number of char in string value
SUBSTRING (Ziqi Ding, 2, 5)
iqi D
,5: count 5 on from start char
How to declare what data type something is
DECLARE Name: STRING
DECLARE Age: CHAR
In Pseudocode does the word number start with 0 or 1
1
