Unit 1 - Fundamentals of programming

Question 1

What is an algorithm?

Answer 1

A sequence of instructions that can be followed to solve a problem.

Question 2

What can relational operators be used for?

Answer 2

To compare values within the expression

Question 3

What are the three types of iteration?

Answer 3

Indefinite iteration with the condition tested at the start of the loop. (While)

Indefinite iteration with the condition tested at the end of the loop.

Definite iteration where the loop is performed a given number of times. (For loop)

Question 4

What is a subroutine?

Answer 4

A set of instructions with a name

Question 5

What is a function?

Answer 5

A subroutine that returns one or more values.

Question 6

What are library subroutines?

Answer 6

Pre-defined subroutines.

Question 7

Where do parameters appear?

Answer 7

In subroutine definitions. They are part of the subroutine definition.

Question 8

Where do arguments appear?

Answer 8

In subroutine calls. They may vary from call to call.

Question 9

What is a local variable?

Answer 9

It can only be used in that subroutine, they are created once a method is entered and cleared once the method is exited.

Question 10

What is a global variable?

Answer 10

it is defined in the main program and can be used in any subroutine called from the main program.

Question 11

What is the scope of variables?

Answer 11

The scope of a local variable is the subroutine which it is declared. The variable does not exist outside the subroutine.

Question 12

What are advantages of local variables?

Answer 12

The subroutines will be independent of a particular program and can be re-used in different programs.
There is no chance of accidentally changing a variable in the main program that is used in a subroutine or vice versa.
Keep your subroutines self-contained!
Pass as arguments any values that are needed.

Question 13

What is modular programming?

Answer 13

Means breaking down a major task into smaller subtasks.

Question 14

What are some advantages of modular programming?

Answer 14

Large programs are broken down into subtasks that are easier to program and manage.
Each module can be individually tested
Modules can be re-used several times in a program.
Large programs are much easier to debug and maintain.
Programs are more easily and quickly written.

Question 15

What does a file consist of?

Answer 15

A number of records.

Question 16

What is a record?

Answer 16

A data structure consisting of a number of fields which can all be of different data types

Question 17

What is a text file?

Answer 17

A text file has fields typically separated by commas, and written one line at a time.
You can create, read and manipulate a text file with any text editor.

Question 18

How do you write a file?

Answer 18

file=open(‘newFile.txt’,’w’)
file.write()

Question 19

What is a binary file?

Answer 19

A binary file can contain records with different types of field such as string, integer, real, Boolean.
Binary files contain bytes.
You can write data to a binary file

Question 20

How do you read a file?

Answer 20

file=open(“newFile.txt”, “r”)
file.read()

Question 21

How do you append to a file?

Answer 21

file=open(‘newFile.txt’,’a’)

Question 22

Why use a binary file?

Answer 22

Text files are convenient because you can read and manipulate them with a text editor, but they can only store a string of characters
Sometimes you need to store a more complex record structure and read it back with the fields intact
A record can store any mix of data types in one unit of data which can be written to a file and read back

Question 23

What is a runtime error?

Answer 23

A runtime error will cause a program to crash.

Question 24

Why do you use exception handling?

Answer 24

Using exception handling statements, you can intercept and handle exceptions so that your program does not crash.

Question 25

How do you code exception handling?

Answer 25

Insert a try… except statement to ensure that it does not crash

Question 26

What are some examples of file handling errors?

Answer 26

Trying to open a file which is not in the specified or default folder.
Reading past the end of the file.

Question 27

Why use a constant?

Answer 27

Constants reduce the risk of errors by reducing access to the memory location
e.g. pi is 3.14159…

Question 28

How can you change the value of a constant?

Answer 28

You have to change it in the source code and then recompile.

Question 29

How can you change the value of a variable?

Answer 29

The value of a variable can be changed while the program is running.

Question 30

What can boolean operators be used for (and, or)?

Answer 30

To link multiple expressions.

Question 31

What is a case statement?

Answer 31

The logical equivalent to the if…then or elif statement.
It can be used to evaluate multiple expressions

Question 32

What does iteration mean?

Answer 32

Iteration means repetition

A sequence of instructions is repeated multiple times

This is much more efficient than writing the instructions multiple times

Question 33

What is an infinite loop?

Answer 33

You may cause an infinite loop if you make a coding error.

Computer control and data sensing applications use infinite loops to gather data from sensors. After the setup code is run, the device enters an infinite loop to repeatedly check the value of the sensors

Question 34

What is an array?

Answer 34

a data structure containing multiple elements all of the same data type, e.g. string, integer, real, etc.