Designs, Systems and Routines

Question 1

Top down design

Answer 1

Breaks down computer system/program into a set of subsystems

each subsystem just performs a single action

Question 2

4 advantages of top down design

Answer 2

1. allows several programmers to work at the same time on the software
2. development time is faster
3. can test each subsystem independently
4. easier to debug

Question 3

Structure chart

Answer 3

modelling tool used to show hierarchy of a system/program

graphical representation to show how a system is broken into subsystems

Question 4

Library routine

Answer 4

block of pre-written code
given a name
carries out common task
can be called from other programs

Question 5

Advantages of library routine

Answer 5

1. makes writing programs easier and faster because code is already written
2. make program testing easier as code has already been tested and debugged

Question 6

Subroutine

Answer 6

A self-contained block of code which is given a name

2 types: function or procedure

Question 7

Procedure

Answer 7

may or may not return a value

Question 8

Function

Answer 8

always returns a value

Question 9

Advantages of subroutine

Answer 9

1. less program codes as subroutine can be written and reused in same program
2. less memory space used
3. can be used in other programs
4. parameter passing