2.2 Programming Fundamentals

Question 1

What is a variable?

Answer 1

A value that can change whilst the program is running. It is simply an address in memory e.g. an integer, character string, real(float) or Boolean.

Question 2

What is a constant?

Answer 2

A value which remains fixed as it does not change while the program is running, and is assigned when the program is running.

Question 3

What is an assignment?

Answer 3

When we give, or supply a value to a variable or constant. It is performed with the ‘=’ symbol.

Question 4

What is an operator?

Answer 4

Symbols used to perform operations on variables and values

Question 5

What is an output?

Answer 5

Data generated by the computer and displayed to the user.

Question 6

What is an input?

Answer 6

A value is read from an input device e.g. Keyboard

Question 7

What is casting?

Answer 7

Converting a variable from one data type to another e.g. integer to a string

Question 8

Advantages of constants:

Answer 8

• Easier to read as they are usually declared and assigned at top of the program
• Less chance of errors
• Makes program run more quickly if used instead of variables

Question 9

Why is casting needed?

Answer 9

• Inputs from keyboards are always characters. Multiple characters are called a string
• Integers require less bits of memory than numbers with a decimal part (real numbers)

Question 10

Data types for constants and variables

Question 11

Three Programming Constructs

Answer 11

Sequence, Selection, Iteration.

Question 12

What is sequence?

Answer 12

Executing one instruction after another

Question 13

What is selection?

Answer 13

Selection is a program branching depending on a condition (if, else, elseif)

Question 14

What is branching?

Answer 14

A construct that allows the program to end up going in a number of various directions depending on the outcome of a condition

Question 15

What is iteration?

Answer 15

Iteration, sometimes called looping, is repeating sections of code until a condition is met. (for loop, while loops)

Question 16

What are while loops?

Answer 16

While loops, known as condition controlled loops are used when the number of iterations is not known because the variable used to determine when the iteration end is changing within the iteration itself.

Question 17

What are DO..UNTIL loops?

Answer 17

An alternative to WHILE where the code is executed at least once before the condition is checked

Question 18

What does the Arithmetic Logic Unit perform?

Answer 18

Arithmetic comparisons, logical comparisons, binary shifts

Question 19

Why is a Boolean operator called Boolean Expression?

Answer 19

The expression equates or evaluates to either true or false

Question 20

What does concatenate mean ?

Answer 20

Join together

Question 21

How do we concatenate numbers?

Answer 21

In order to concatenate them, and not simply add them they need to be stored as a string data type

Question 22

How can you perform arithmetic operations on values?

Answer 22

Converts string data types back into integers or any other data types to perform arithmetic operations on values

Question 23

What is a value entered from the keyboard inputted as?

Answer 23

Characters

Question 24

Why is casting necessary?

Answer 24

It is so subproblems receive data in a format they are expecting

Question 25

What does casting allow?

Answer 25

• numbers to be manipulated as strings
• inputs that are strings to become numbers

Question 26

What is an array?

Answer 26

A variable which contains more than one data item e.g. storing a list of names

Question 27

What does contiguous mean?

Answer 27

All the data is stored together, one element after another

Question 28

What does index start with?

Answer 28

It starts with 0

Question 29

What is append?

Answer 29

Asserting a new item into new location at end of array using an index

Question 30

How is the element (particular data item) found?

Answer 30

Using the index

Question 31

Are arrays single and multiple dimensions?

Answer 31

They are both

Question 32

What is a flowchart?

Answer 32

A method of representing sequences of steps in an algorithm in form of a diagram

Question 33

What is pseuodocode?

Answer 33

Alternative text-based way of representing sequence of steps in an algorithm

Question 34

Advantages of using sub programs

Answer 34

Easier to write/read and debug and creates reusable components

Question 35

What are sub-routines?

Answer 35

Larger programs developed as a set of sub-programs

Question 36

What do functions do?

Answer 36

Return values and create reusable program components

Question 37

What do procedures do?

Answer 37

Create a modular structure to a program making it easier to read