N5 Software

N5 Software Design and Development

National 5 Computing Science Miss Lyon

Software Design & Development

• ​Development Methodologies

• Analysis

• Design

• Implementation

• Testing

• Evaluation​

N5 Computing Science

Development Methodologies

The 6 stages of the software development process are:​

• Analysis - identify what the program is meant to do

• Design - design the algorithm and user interface

• Implementation - make the program

• Testing - check the program works as expected with no errors

• Evaluation - check the program meets the requirements

​​The development process is iterative meaning stages can be revisited

N5 Computing Science

Multiple Choice

Which is not a step of the development process?

• Analysis

• Design

• Reporting

• Implementation

Multiple Choice

The software development process is described as iterative because...

• each stage must be followed in the exact order

• each stage can be revisited to improve the final solution

• you can chose the order to do each stage

• you have to repeat every stage in the process

Analysis

The inputs, processes and outputs of a program​.

Example: A program should ask the user to input the radius of a circle. The program should then calculate and display the area and the circumference of the circle.​

​

​

Functional Requirements

Identify the purpose of a software problem. This is usually describing what the program must do.

Purpose

Multiple Choice

What is the main purpose of the analysis stage in the software development process?

• Determining exactly what the user requires

• Deciding a strategy for solving the problem

• Creating pseudocode

• Making sure that the program is fit for purpose

Design

A 1D Array would be used to store multiple values of the same data type.

Example:

​Q - A program is required to store the temperature for each day of the week. Temperatures are recorded to 1 decimal place.

State which data structure would be used in this program.

​​A - A 1-D array of type real

​

Data Structures

• Character ('A', 'B', 'Z')

• ​String ('Hello', 'World')

• Integer (19, -8)

• Real (3.2, 16.755)

• Boolean​ (True, False)

Note: Character is not a data type in Python - but you still need to ​know about it.

Data Types (especially real) are often given different names in programming languages. You should use the terms above in the exam.​

Data Types

Multiple Choice

Which data type is used to store:

100

• Integer

• Character

• Boolean

• String

Multiple Choice

Which data type is used to store:

TRUE

• Boolean

• Real

• String

• Integer

Multiple Choice

What data type would you store a vehicle's registration plate?

• Real

• String

• Boolean

• Integer

Multiple Choice

What type of data would you use to store whether someone wanted to sign up for promotions or not?

• String

• Boolean

• Real

• Integer

Multiple Choice

Which data type or structure would be used to store a list of names for everyone in your class?

• string

• array of strings

• array of reals

• variable

Design - Design Notations

A graphical method of showing the algorithm. Follow the arrows showing the flow of data through the program.

Flowcharts

A graphical method of showing the algorithm. Read from top to bottom, left to right.

Structure Diagrams

We require design notations to show the steps of an algorithm to solve a problem

Design - Design Notations

A wireframe is user to design the user interface of a program.

This should show how the screen layout along with any inputs and outputs.

It could look ike either of the examples below depending on the programming environment you are using.​

​

UI Design

Pseudocode is a way of designing the steps of a program using phrases that resemble lines of program code

Pseudocode

We require design notations to show the steps of an algorithm to solve a problem

Multiple Choice

Name this design technique

• Wireframe

• Flowchart

• Pseudocode

• Structure Diagram

Multiple Choice

Name this design technique

• Wireframe

• Flowchart

• Pseudocode

• Structure Diagram

Multiple Choice

Name this design technique

• Wireframe

• Flowchart

• Pseudocode

• Structure Diagram

Implementation - Data Types and Structures

An array is also a storage location in a computer program however, an array can store a collection of data of the same data type.

1D Arrays

A variable is a storage location in a computer program.

Only one value can be held at a time​.

The variable must have a meaningful name and a data type.​

Variables

Multiple Choice

The following array is created in a program: " DIREWOLVES = ["Nymeria","Shaggy Dog","Ghost","Lady","Grey Wind","Summer"]

What is the item stored in DIREWOLVES [2] ?

• "Shaggy Dog"

• "Ghost"

Implementation - Computational Constructs

Concatenation means joining two or more strings together.

Concatenation

Arithmetic operations are used to carry out calculations.

There are arithmetic operators for:

• + Add

• - Subtract

• * Multiply

• / Divide

• ^ Exponent (to the power of)

Arithmetic Operations

Multiple Choice

Joining elements together to make a string is called what?

• Combining
• Connecting
• Concatenation
• Stringing

Multiple Choice

What is Concatentation

• The process of joining strings and variables

• The process of inputting data into a variable

• The way we find errors in a program

• The way selection is used

Multiple Choice

Arithmetic Operator
What is a * ?

• Addition
• Subtraction
• Multiplication
• Modulo

Multiple Choice

What is stored in the variable 'answer'?

answer = 3^2

• 6

• 9

• 3

• 2

Implementation - Computational Constructs

A complex condition means there are two or more rules being tested e.g.

• exam_mark >= 50 AND exam_mark < 60

• temperature < 0 OR temperature > 200

• number = 1 OR number = 3 OR number = 5

AND, OR, NOT are examples of logical operators​

Complex Conditions

A simple condition means there is only one rule being tested​

e.g.

• choice = "A"

• temperature < 0

• exam_mark >= 70

Simple Conditions

In programming, selection means making a decision. The IF statement is used to make a decision.

The condition is the rule that is being tested by the IF statement​.

Multiple Choice

The logical operator 'or' means that...

• only one condition has to be true

• both conditions must be true

• the condition must be false

Multiple Choice

The logical operator 'and' means that...

• only one condition has to be true

• both conditions must be true

• the condition must be false

Multiple Choice

What is the output of the code below?

x = 5

if x == 0:

print("x is 0")

elif x > 1:

print("x is greater than 1")

elif x > 3:

print("x is greater than 3")

• x is 0

• x is greater than 1

• x is greater than 3

Multiple Choice

What is the output?

• more than 7

• more than 23

• spam

• 7

Multiple Select

Identify the logical operators in the code

• AND

• NOT

• OR

Implementation - Computational Constructs

A conditional loop will execute while a specific condition is being met, or until a specific condition is met.

​

​

WHILE number < 1 DO

SEND "Error, please enter number again" TO DISPLAY​

Conditional Loop

A fixed loop will always execute a fixed number of times.

​

​

FOR counter FROM 1 TO 10 DO SEND counter TO DISPLAY​

Fixed Loop

Multiple Choice

What type of loop is this?

• Fixed

• Conditional

Multiple Choice

In programming, what is iteration/looping?

• The repetition of steps within a program

• The order in which instructions are carried out

• A decision point in a program

Multiple Choice

Why is iteration important?

• It determines the order in which instructions are carried out
• It allows code to be simplified by removing duplicated steps
• It allows multiple paths through a program

Multiple Choice

Which type of loop is being used in this program?

• Fixed loop

• Conditional loop

Multiple Choice

What would stop the conditional loop in this example program?

• When the user has guessed the number more than 10 times

• When the user guesses higher than the number 54

• When the user guesses lower than the number 54

• When the user guesses the number 54

Implementation - Computational Constructs

A pre-defined function is an in-built function within the programming language.

You are required to know three functions at National 5.

​

• Random - returns a random number between two parameters.

  ​SET number TO random(1, 10)

• Round - returns a decimal number rounded to a given number of places

  ​SET result TO round(6.7854, 2)

• Length​ - returns the length of a string

  ​character_count = length("Hello World")

Pre-defined Functions

Multiple Choice

Which pre-defined function would be most suitable to format a number to look like a sum of money?

• length

• function

• round

• random

Multiple Choice

Which pre-defined function would be most suitable to generate a winning raffle ticket number?

• function

• length

• round

• random

Multiple Choice

Which pre-defined function would be used to find the number of characters in a string?

• function

• length

• round

• random

Multiple Choice

What would be the output of running the following code:

• 3.1415

• 3.142

• 3.1416

• 3.14159

Implementation - Standard Algorithms

The Input validation algorithm checks that the user input is acceptable.​

​

Input Validation always makes use of a conditional loop.

​

SEND "Enter a number between 1 and 10" TO DISPLAY

RECEIVE number FROM KEYBOARD

WHILE number < 1 OR number > 10 DO

SEND "Invalid - enter a number between 1 and 10" TO DISPLAY

RECEIVE number FROM KEYBOARD

END WHILE

​

​

​

Input Validation​

Implementation - Standard Algorithms

The running total algorithm adds a list of values.

​

Running Total algorithms always make use of a fixed loop.

​

​DECLARE total INITIALLY 0

FOR counter FROM 1 TO 5 DO

DISPLAY "Enter a number"

RECEIVE number FROM KEYBOARD

SET total TO total + number

END FOR

SEND total TO DISPLAY

​

​

​

Running Total

Implementation - Standard Algorithms

The traversing an array algorithm accesses each element of an array from first to last.

​​

​DECLARE test_scores INITIALLY [34, 75, 56, 60, 18]

DECLARE passes INITIALLY 0

FOR counter FROM 0 TO 5 DO

IF test_scores [counter] >= 50 THEN

SET passes TO passes + 1

END IF

END FOR

SEND passes & " students passed" TO DISPLAY

​

​

​

Traversing an array

Multiple Choice

Name this standard algorithm

• Running total within a loop

• Input validation

• Traversing an 1D array

Multiple Choice

The program below traverses an array of countries and displays each in turn.
Which of the following statements has been removed from line 3?

• DISPLAY countries

• DISPLAY countries[counter]

• DISPLAY counter

• DISPLAY countries()

Multiple Choice

What will be the output from this program?

• 31
  27
  17
  25
  41

• 27
  17
  25

• 31
  41

• 41

Multiple Choice

Name the standard algorithm that has been used in the following program.

• Input validation

  
  

• String concatenation

  
  

• Running total within a loop

  
  

• Traversing an array

  
  

Multiple Choice

The program below uses input validation to ensure response is either 'P' or 'Q'.
Which of the following statements has been removed from line 13?

Multiple Choice

The program below uses the running total in a loop algorithm to add 10 ratings entered by the user.
Which of the following statements has been removed from line 1?

Testing - Test Data

Multiple Choice

Which is NOT a level of testing?

• Normal

• Extreme

• Exceptional

• Extraordinary

Testing - Errors

An error that occurs when the program is running. An instruction that the computer cannot execute.

E.g. Dividing by 0​ or inputting a number when the program expects a string

Execution

Breaking the rules of the programming language.

Usually the result of a typing error. Misspelled words or missed punctuation like " " ( )

The program will usually crash and not run​.

Syntax

Logic

This error causes the program to operate incorrectly but not crash. Usually the result of an incorrect calculation or wrong logical operator.

Multiple Choice

Which is NOT an error?

• Logic

• Execution

• Syntax

• Intentional

Multiple Select

State the two types of errors in the code

• Syntax

• Logic

• Execution

Evaluation - Readability

• internal commentary

• meaningful variable names

• indentation

• whitespace​

A program is made more readable through use of:

Multiple Choice

Which are examples of ways to aid code readability.

• Use internal commentary

• Use meaningful variable names

• Use white space

• All of them