Algorithm

Question 1

Name 4 algorithm design cycles (4 marks)

Answer 1

Problem analysis: Identify a problem so that a program can be made solve that problem

Algorithm designing: Details about the solution is set out

Coding: Develop the actual program

Testing: Repeat the program with different set of data to debug any bugs

Question 2

Describe 2 ways for problem analysis (2 marks)

Answer 2

Abstraction: Focus onto the main problem and disregard any unnecessary details

Decomposition: breaking down a large problems into smaller, simple problems

Question 3

Describes 2 ways for algorithm designing (2 marks)

Answer 3

Flowchart and pseudocode

Question 4

Describe the uses of all of the following shape in flowchart (4 marks)

Rounded rectangle
Rectangle
Diamond
Parrallelogram
Flow lines

Answer 4

Rounded rectangle: Start/end (terminator)
Rectangle: To describe actions/sequences & assigning variables (not from users)

Diamond: To describe selection & repetititon
Parrallelogram: Input & Output

Flow lines : To show flow of action

Question 5

Name of types of data (6 marks)

Answer 5

Boolean: True/False
String: Text/ words
Char: a single character

Integers: Numbers
Real: Decimal
Alphanumeric: both integers and string

Question 6

Components part of computer systems (4 marks)

Answer 6

Input: giving in data
Output: Displaying data
Process: the tasks needed to be performed with the inputted data to display output data.

Storage: data is kept for future use

Question 7

What is validation (1 mark)

Answer 7

To check if the data entered follow the rules set by the programmer

Question 8

Examples of validation (6 marks)

Answer 8

Format: To see if the data entered follow a certain structure (@gmail.com)
Type: To see if the data entered match with the type of data
(boolean,string,char,real,alphanumerical or intergers)

Range : To see if the data entered fall within the range
Length: To see if the data entered has enough of characters/ integers

Presence : To see if the data has been entered
Check digit: Value calculated

Question 9

What is verification? ( 2 marks)

Answer 9

To check if the data entered is what the user intended to type in
To check if the data is copied from a source to another is the one the user intended to input.

Question 10

Example of verification (2 marks)

Answer 10

Double entry: re-type the same data twice
Visual check: look back at the data to see if they are what you intended to type

Question 11

How to make an algorithm easier to understand (4 marks)

Answer 11

• Meaningful identifiers
• Adding comments
• Uses of white spaces
• Use of functions

Question 12

What are the 3 types of test data (3 marks)

Answer 12

Valid data: Data which will be accepted
Extreme data: Data that is the limits of the range that should be accepted (like 1 or 99 in 0<x<100)
Invalid data/abnormal data: Unacceptable data

Question 13

What are fields and records in database? (2 marks)

Answer 13

Field = Columns
Record = Rows (not including the first section)

Question 14

What is a primary key? (1 mark)

Answer 14

An unique data to identify other records

Question 15

What is a subroutine? (1 mark)

Answer 15

A section of the program that is specified to do a specified task

Question 16

What is a function? (3 marks)

Answer 16

• Function is called by its identifers
• Parameters are passed onto the function
• It will perform all the required operations and return a value back to the main program

==> function is a subroutine that can return a value

Question 17

What is a procedure? (1 mark)

Answer 17

A subroutine that CAN’T return any value back to the main program

Question 18

What is a constant? (1 mark)

Answer 18

Stores a value that can’t be changed during the program execution

Question 19

Difference between global & local variables ( 4 marks)

Answer 19

Local: Scope is subroutine,procedure or function
Global: Scope is the whole program

Local: Can’t be changed elsewhere in the program
Global: Can be changed anywhere within the program