algorithm design and problem solving

Question 1

whats pdlc

Answer 1

program development life cycle
steps followed in developing a program

Question 2

what are the steps in pdlc and what do they stand for

Answer 2

analysis- understanding inputs needed and if enough resources available
design- technical and visual aspects of product
coding- programming implementation of design and analysis
testing- testing if program functions in intended way

Question 3

what happens if program doesnt work in inteded way

Answer 3

process loops, goes back to analysis stage to find problem and how to fix it, this is called iteration

Question 4

what are the three parts of the analysis stage

Answer 4

abstracting problem
decomposing problem
identifying requirements

Question 5

describe the abstracting problem phase in analysis

Answer 5

abstraction- process of including only specific details of problem higher level of abstraction is more removed program is from direct control of cpu

Question 6

describe the decomposing problem phase in analysis

Answer 6

process of breaking big probelm into smaller manageable chunks

Question 7

describe the indentifying requirements phase in analysis

Answer 7

requeirements- specific mandatory conditions, must be carried out to be certain of final outcome
question on requirements usually passed to client or user by program designer

Question 8

describe design stage

Answer 8

representing program before writing code, expresses how code would work what input are how logic would be coded etc.
involves similiar decomposition stage to the anaylisis stage, includes 3 representations structure diagram, flowchartm and pseudocode

Question 9

what are the processes in the design stage

Answer 9

client feedback
ease of sharing- feedback from other programer
ease of modification- where to implement amendments

Question 10

what are the three representations possible in design stage

Answer 10

flowchart
pseudocode
strucutre diagram

Question 11

describe structure diagrams

Answer 11

represent sub systems, each level is less abstracted than above
helps to split and delegate development work to teams
help identify which part needs debugging

Question 12

describe flowcharts and components

Answer 12

indicates inputs needed and process to be followed
-> = arrow represents control between shapes, order to be followed
rectangle = process, something being performed eg. declaring
parallelogram= input/ output of data
diamond= decision, results in two lines representing different outcomes eg. if statement
oval= start and stop

Question 13

describe pseudocode

Answer 13

actual code, not understood by computer, only by humans

Question 14

describe coding stage

Answer 14

written in ide- which organises code, debugs, supports many programming languages
has iterative testing in between coding stage

Question 15

what is meant by iterative testing

Answer 15

testing carried out in coding stage
iterative= action carried in a loop until correct outcome
splitting up longer code into smaller chunks called modules
iterative testing applied to each module during coding phase

Question 16

describe testing phase

Answer 16

make sure program works as inteded
iterative testing regularly carried out during coding, 6 different tests that can be carried out

Question 17

unit testing

Answer 17

done by yourself, programmer, on pieces of code that you have written

Question 18

integration test

Answer 18

putting all modules together testing complete system

Question 19

system testing

Answer 19

testing software app you have built

Question 20

dryrun testing

Answer 20

programmer goes over everyline of code and traces how program will bhave

Question 21

alpha testing

Answer 21

prototype product tested by yourself

Question 22

beta testing

Answer 22

near final product testing on sample target audience

Question 23

what are the different testing that can be done

Answer 23

unit testing, integration test, system testing, dryrun testing, alpha testing, beta testing

Question 24

what are the different test data

Answer 24

normal data, boundary data, extreme data, abnormal data

Question 25

normal data

Answer 25

data that are inbetween ranges, should be exepted

Question 26

boundary data

Answer 26

pair of values indacting lower and upper boundary 2 should be exepted and 2 shouldnt eg. if range is between 1-10 including 1 and 10 0, 1, 10, 11 would be boundary data

Question 27

extreme data

Answer 27

data at upper and lower bounds are inaccepted range

Question 28

abnormal data

Answer 28

any data that should not be accepted, outside range, not correct data type

Question 29

what processes of computer systems are included in structure diagram- decomposing problem

Answer 29

input process output storage

Question 30

describe input part of structure diagram

Answer 30

how system receives input what kind of inputs needed more than one source of input does input depend on output

Question 31

describe process part of structure diagram

Answer 31

primarily requires calculations/ decision/ retrieval of data either serial or parallel what does system do to get output how is input turned into intended output how many tasks does it take

Question 32

describe output part of structure diagram

Answer 32

what kind of output does machine produce what devices does machine use to deliver output more than one form of output

Question 33

describe storage part of structure diagram

Answer 33

where does data go after output is it stored what kind of data is stored

Question 34

what is meant by a variable

Answer 34

stores data value in program, values can be changed, data varies

Question 35

what is meant by constant

Answer 35

value in a program that isnt altered

Question 36

what is an array

Answer 36

stores only same type of data, each element has a unique position, organised sequentially, fixed size, first and last position is known as upper and lower bound

Question 37

what is meant by linear search

Answer 37

algorithm where an array is searched sequentially until searched value is confirmed presence or absence, stops either when value found, or when array ends, each value assigned true or false, true= has value

Question 38

what is meant by bubble sorting

Answer 38

placing data elements in a particular order, in this case either from larger to smaller or vice versa everytime a pair of value in data array are reordered= swap each time full set of values in array have been examined and swapped if necessary= pass

Question 39

what is meant by totalling

Answer 39

running total along program, adds current value by previous eg. total= total + weight

Question 40

what is meant by counting

Answer 40

increasing current value by 1 also called incrementing by 1 eg. count= count + 1

Question 41

what is meant by finding max and min

Answer 41

finding largest and smallest value in a array

Question 42

what is meant by average

Answer 42

sum of all values/ number of values

Question 43

what is validation

Answer 43

making sure data entered is sensible and meaningful, automatic check ensures data correct type and in range 6 types

Question 44

range check

Answer 44

verifies if entered value falls within specified range

Question 45

length check

Answer 45

validates data based on length or max numbers of characters eg. when writing a password

Question 46

type check

Answer 46

confirms correct type of data enter

Question 47

presence check

Answer 47

ensures data is present in expected place, eg when answering a form

Question 48

format check

Answer 48

input uses specific format eg when entering data of birth must be using forward slashes

Question 49

check digit

Answer 49

uses one or two specific characters in a sequence of digits to validate input eg. barcode

Question 50

what are the different checks used in validation

Answer 50

range, length, type, presence, format, check digit

Question 51

verification

Answer 51

process helps to check if data entered is correct by matching entered data to expected value visual check double entery check

Question 52

describe visual check

Answer 52

user manually verifies data they inputed against original source of same data, not automated, protects against data errors

Question 53

describe double entry check

Answer 53

automated verification check, system asks user to retype same data, compares both entered data must match

Question 54

tracetables

Answer 54

method of manually following your code, recording values the computer assigns to each variable, identifies problems in algorithms and debugging a program