paper 2 dk

Question 1

BY REF or BY VAL

Answer 1

By value
- If variable is used the value cant be changed within the procedure
By reference
- The value passed in can be changed by the procedure

Question 2

how to test to expose a fault

Answer 2

• dry run
• write output statements to track the code
• breakpoint/ single stepping/ report window
• try test values to see which fail

Question 3

disadvantage of a linked list

Answer 3

more complex
store pointer and data

Question 4

meaning of up and down arrows in waterfall model diagram

Answer 4

down - result from one stage is passed to the next
up - more work required at the previous stage to complete the current stage

Question 5

procedure call pseudocode

Answer 5

CALL PROCEDURE()

Question 6

state of queue is front and end pointers same

Answer 6

one data item in it

Question 7

3 thinsg that take place during design

Answer 7

• data structures decided on
• algorithms / flowcharts/ pseudocode created
• program structure and modules created
• test method chosen
• programming lang chosen

Question 8

advantages of having less modules

Answer 8

+ only have to change one module if spec changes
+ less repetitive code
+ aids reusability

Question 9

insertion sort

Question 10

concatenation pseudocode

Answer 10

&

Question 11

principle of RAD

Answer 11

minimal planning/ flexible process

Question 12

2 reasons for adaptive maintenance

Answer 12

• requirements change
• new tech available
• change in legislation

Question 13

procedure interface

Answer 13

provides a mechanism to allow calling a program to pass data
defines the parameters giving their data type and order
- Must match the procedure/function definition
- Parameters must match those in the definition – in type and in order

Question 14

+ constant

Answer 14

• only needs to be changed once
• prevents input error
• makes program easier to understand
• less repeated code

Question 15

file operations - input, process, output

Answer 15

write file - output
read file - input

Question 16

additional info needed for walkthrough

Answer 16

source code or inputs and expected outputs
- structure/ design of algorithm needs to be known
- so all paths can be tested

Question 17

stepwise refinement

Answer 17

decomposition breaks problems down into smaller parts
these parts are written as a series of steps where each can be written in a high level lang

Question 18

program development lifecycle

Answer 18

analysis
design
coding
testing
maintenance

Question 19

walkthrough

Answer 19

used predefined test cases where another member dry runs the pseudocode - check specific areas

Question 20

ADT

Answer 20

• Collection of data and a set of operations on that data

Question 21

loops

Answer 21

• Count controlled
• Pre condition
• Post condition

Question 22

waterfall

Answer 22

• Each stage completed before the next is begun, fully documented, low customer involvement

Question 23

iterative

Answer 23

• Subset of requirements is developed then expanded or enhanced – repeated until full system has been developed, working parts produced at each iteration, high customer involvement

Question 24

RAD

Answer 24

• Different parts of requirements are developed in parallel using prototyping to provide early user involvement, minimal planning, reuses pre written code, high customer involvement

Question 25

dry run

Answer 25

– developer works through a module manually and documents results in a trace table

Question 26

walkthrough

Answer 26

– formalised dry run using pre defined test cases, another member dry runs the pseudocode

Question 27

white box

Answer 27

– testing how each procedure works, involves testing the structure and logic of every path

Question 28

alpha

Answer 28

– tested by in house development team

Question 29

black box

Answer 29

– tests inputs and outputs

Question 30

maintenance

Answer 30

- corrective – corrects errors in use - perfective – improves performance of program - adaptive – alters program to perform new tasks

Question 31

things produced after analysis

Answer 31

requirement spec system objectives problems with existing system