Software Development

Question 1

What is a variable

Answer 1

Programmers use variables to store pieces of data whilst the program is running.
•If the user is asked to enter information into a program then it needs to be stored – so a variable is created.
•A variable is a temporary storage space that can store one piece of data.

Question 2

The 6 different Variable types

Answer 2

oCharacter
oString
oInteger
oReal
oBoolean
o1-D Arrays

Question 3

variable type-character

Answer 3

only stores one character. E.g. S, k, P

Question 4

Variable type - string

Answer 4

can contain a mixture of letters, numbers and characters. E.g. hello, FK6 5EE, mrsbrown@hotmail.co.uk

Question 5

Variable type- interger

Answer 5

whole numbers, both positive and negative. Cannot contain anything else. E.g. 11, 999, -128

Question 6

Variable type - real

Answer 6

numbers that contain a fraction or decimal. E.g. 0.09, 10.2, 1567.87

Question 7

Variable type - Boolean

Answer 7

has only two states, true or false.

Question 8

Data structure - 1D array

Answer 8

(For the purposes of this course you only need to know about 1 Dimensional Arrays.)
•1-D Array – used to store a list of variables, that are all of the same data type.
•E.g. harry, sam, peter 12, 16, 18

Question 9

What are the 6 stages of the software development process

Answer 9

Analysis - This is where the problem is analysed and the programmer ensures that they know exactly what they are meant to do.
Design – A solution to the problem is designed using a variety of design techniques. Design decisions are made at this stage.
Implementation – The solution is created.
Testing – Solution is tested using test data, errors are identified and corrected.
Documentation – The paperwork is completed. A technical guide and a user guide are written.
Evaluation – The solution is examined to make sure that it meets the specification and is fit for purpose.

Question 10

Why is the Software development process known as an iterative process

Answer 10

The SDP has 6 stages that are worked through in order. However, sometimes new information means that a previous stage has to be revisited. This is iteration.

For example, During the testing stage it might be discovered that there is an error in the code. This would mean that the implementation stage needs to be revisited.

Question 11

Test data types

Answer 11

normal, extreme and exceptional.

Question 12

Test data - Normal

Answer 12

data that is within range, of the correct data type and should be accepted.

Question 13

Test data- Extreme

Answer 13

data that is on the edge of what should be accepted but should be accepted

Question 14

Test data - exceptional

Answer 14

data that is out of range or the wrong data type. It should not be accepted.

Question 15

Different types of errors

Answer 15

Syntax,execution,logic

Question 16

Error type - Syntax

Answer 16

where the rules of the programming language are broken. Commonly a spelling mistake, missing out an end if, a full stop in the wrong place

Question 17

Error type - Logic

Answer 17

are mistakes in the design of the program. They are only spotted when the program is run because the program still works, but does not produce the expected result.

Question 18

Error type - Execution

Answer 18

also known as a runtime error. These errors show up when the program is run. Perhaps there is not enough allocated space in memory and a large number cannot be stored accurately.

Question 19

Evaluation- Fitness for Purpose

Answer 19

Does the program solve the original problem?
•Does the program meet the software specification that was created at the Analysis stage? Any differences should be accounted for.
•Do the actual test results match the expected test data results?

Question 20

Evaluation- efficient use of coding constructs

Answer 20

•Is the program efficient?
•Does it have unnecessary lines of code?
•Do all the loops repeat the correct number of times?
•Could the code have been written more efficiently?

Question 21

Evaluation- Robustness

Answer 21

•How does a program cope with an error when it is running?
•Does it fail and stop?
•Does it have input validation built in that allows data to be re-entered and the program to continue?
•If the printer jams or runs out of paper that should not stop a program from running. A robust program would contact the user and say that there was an error with the printer.

Question 22

Evaluation- Readability

Answer 22

Readability is how straightforward it is for another programmer to look at code and understand the purpose of the code, or be able to fix an error.

Internal Commentary – Comment lines. This helps to explain what certain lines of code are actually doing. Comment lines do not affect the running of the program

Indentation – Indenting loops and if statements can help you to spot if and end if has been missed, or if code is outside a loop when it should be inside. It makes it easier for another programmer to follow the code.

Question 23

What is a conditional loop

Answer 23

A Conditional Loop is a structure which is used when the number of times a section of code is repeated is not known, and depends on one or more conditions being met.

Question 24

What is a fixed loop

Answer 24

A fixed loop is a structure in which the programmer sets the number of times a loop must be repeated. It is used when the programmer knows in advance how many times the code should be repeated. A loop variable keeps track of how many times the loop has executed

Question 25

What is a 1D array ?

Answer 25

A 1-D array is an example of a data structure. It is used to store a list of items that are the same data type.

Each element in an array is identified by the variable name and the element number or index, which identifies the position of the element in the arra

Question 26

How to declare an array

Answer 26

You should declare the array and its size at the start of a program, so the computer sets aside the correct amount of memory space (RAM) for the array
Example- products = [‘’] * 20