CIE IGCSE COMPUTER SCIENCE -
PROBLEM SOLVING AND DESIGN EXAM
QUESTIONS AND ANSWERS
Computer System - Answer-is made up of software, data, hardware, communications
and people
Top-down design - Answer-is the breaking down of a computer system into a set of sub-
systems, then breaking each sub-system down into a set of smaller sub-systems, until
each sub-system just performs a single action.
Structure Diagrams - Answer-this shows the design of a computer system in a
hierarchical way, with each level giving more detailed breakdown of the system in sub-
systems
Library Routine - Answer-is a set of programming instructions for a given task that is
already available for use. It is pre-tested and usually performs a task that is frequently
required.
Sub-routines - Answer-is a set of programming instructions for a given task that forms a
sub-system, not the whole system.
-written in high-level programming languages, called functions or procedures
Set of test data - Answer-is all the items of data required to work through a solution
Validation - Answer-this is a automated checking by a program that data is reasonable
before it is accepted into a computer system
Verification - Answer-is checking that data has been accurately copied onto the
computer or transferred from one part of a computer system to another
Methods of verification - Answer--double entry: the data is entered twice, the computer
checks to see that both entries match if they don't the user is prompted to enter the data
again.
-visual check: is a manual check completed by the user who is entering the data.
Standard methods of solution - Answer--some tasks are needed frequently. (e.g. taking
the square root of a number)
-can be provided by a high-level language as a standard function/procedure.
- library routines
Trace table - Answer-can be used to record the results from each step in an algorithm; it
is used to record the value of an item (variable) each time it changes.
PROBLEM SOLVING AND DESIGN EXAM
QUESTIONS AND ANSWERS
Computer System - Answer-is made up of software, data, hardware, communications
and people
Top-down design - Answer-is the breaking down of a computer system into a set of sub-
systems, then breaking each sub-system down into a set of smaller sub-systems, until
each sub-system just performs a single action.
Structure Diagrams - Answer-this shows the design of a computer system in a
hierarchical way, with each level giving more detailed breakdown of the system in sub-
systems
Library Routine - Answer-is a set of programming instructions for a given task that is
already available for use. It is pre-tested and usually performs a task that is frequently
required.
Sub-routines - Answer-is a set of programming instructions for a given task that forms a
sub-system, not the whole system.
-written in high-level programming languages, called functions or procedures
Set of test data - Answer-is all the items of data required to work through a solution
Validation - Answer-this is a automated checking by a program that data is reasonable
before it is accepted into a computer system
Verification - Answer-is checking that data has been accurately copied onto the
computer or transferred from one part of a computer system to another
Methods of verification - Answer--double entry: the data is entered twice, the computer
checks to see that both entries match if they don't the user is prompted to enter the data
again.
-visual check: is a manual check completed by the user who is entering the data.
Standard methods of solution - Answer--some tasks are needed frequently. (e.g. taking
the square root of a number)
-can be provided by a high-level language as a standard function/procedure.
- library routines
Trace table - Answer-can be used to record the results from each step in an algorithm; it
is used to record the value of an item (variable) each time it changes.
