Section 2 - Programming

Question 1

What are the five data types and what type of data are they used for?

Answer 1

• – Integer: a whole number
• – Float: a decimal number
• – Boolean: true or false
• – Character: a single character like a letter, number etc.
• – String: zero or more characters

Question 2

What is an example of definite iteration?

Answer 2

FOR i

Question 3

What is an example of indefinite iteration with the condition at the start?

Answer 3

WHILE Notsolved
Instructions here…
ENDWHILE

Question 4

What is an example of indefinite iteration with the condition at the end?

Answer 4

REPEAT
Instructions here…
UNTIL Solved

Question 5

What is nested selection and nested iteration?

Answer 5

This is when you have a selection or iteration programme within another selection or iteration programme.

Question 6

What are the seven arithmetic operations?

Answer 6

Arithmetic operations:
\+ (addition)
- (subtraction)
* (multiplication)
/ (division) 
^ (exponential)
// (DIV): outputs whole number of division
% (MOD): outputs reminder of division

Question 7

What are the six comparison operators?

Answer 7

Comparison operations:
< (less than)
> (greater than)
<= (less than or equal to)
>= (greater than or equal to)
!= or <> (not equal to)
= or == (equal to

Question 8

What are the three logical operations for boolean expressions and when are they used?

Answer 8

• – AND: when both expressions are true
• – OR: when only one expression needs to be true
• – NOT: inverses true to false and false to true

Question 9

What are two advantages of using arrays?

Answer 9

• – Codes are easier to follow and easier to debug and maintain
• – Can easily be processed by a FOR loop

Question 10

How do you get the length, substring and position of a string?

Answer 10

Length:
— LEN (stringExp) e.g. LEN (“Hello World”) would evaluate to 11

Substring:
— SUBSTRING (startPos, endPos, stringExp) e.g. SUBSTRING (3, 8, “Hello World”) evaluates to “lo Wor”

POSITION:
— POSITION (stringExp, char) e.g. POSITION (“Hello World”, d) evaluates to 10

Question 11

What is concatenation?

Answer 11

Concatenation:

— Joining two or more strings together

Question 12

How do you convert characters to and from ASCII?

Answer 12

CHAR_TO_CODE (“A”) evaluates to 65

CODE_TO_CHAR (66) evaluates to “B”

Question 13

What are the functions you would use for these string handing operations:

• – String to integer
• – String to real
• – Integer to string
• – Real to string

Answer 13

• – STRING_TO_INT (StringExp) e.g. STRING_TO_INT (“45”) evaluates to 45
• – STRING_TO_REAL (StringExp) e.g. STRING_TO_REAL (“72.5”) evaluates to 72.5
• – INT_TO_STRING (StringExp) e.g. INT_TO_STRING (21) evaluates to “21”
• – REAL_TO_STRING (StringExp) e.g. REAL_TO_STRING (3.142) evaluates to “3.142”

Question 14

What is a subroutine?

Answer 14

Subroutine:

— A named “out of line” block of code that is executed (called) by simply writing its name in a program statement.

Question 15

What is the function used for random number generation in python and pseudocode?

Answer 15

Python:
import random
x = random.randint(1,10)
print(x)

Pseudocode:
x = RANDOM_INT (1,10)

Question 16

What are the advantages of using subroutines?

Answer 16

• – Makes problem easier to solve.
• – Can be used several times within a program.
• – Can be stored in a subroutine library and used in other programs.
• – Several programmers can work on a program together.
• – Program maintenance is easier as its easier to change a problem in a subroutine.

Question 17

What is the difference between procedures and functions?

Answer 17

They are both self-contained sections of code that carry out a specific task however a function returns a value using a RETURN statement.

Question 18

Explain local variables and give advantages of them.

Answer 18

Local variables are variables found within a subroutine.
Local variables:
— only exist while the subroutine is executing
— are only accessible within the subroutine.

Advantages:

• – Keeps subroutine self-contained which limits confusion between global variables
• – Keeps program easier to debug and maintain
• – Saves memory as space is freed up when subroutine completes.

Question 19

What is meant by testing in the context of algorithms and programs?

Answer 19

Tesiting is the act of checking if a program runs the way it was intended to run and produces the output expected.

Question 20

Compare the three types of errors when programming.

Answer 20

Syntax error:
— Spelling or grammar mistakes so when there are mistakes in the actual typing up of the code

Logic error:
— Problems with the actual execution of the code in the sense that although the program may run, it does not produce the expected outcome.

Runtime error:
— When the program crashes while the program is being executed. Possibly caused by an incorrect input midway through the program

Question 21

What is test data and describe the three types of test data?

Answer 21

Test data:
— Data that is entered to check if a program works effectively.

Normal (typical):
— Data within the allowed range so data that is valid

Boundary:
— Data which includes both ends of the allowed range as well as data just either side of the allowed range.

Erroneous:
— Any data that falls outside the allowed values and should be rejected by the system.

Question 22

What are the four columns needed in a test plan table?

Answer 22

• – What is being tested
• – Test data
• – Expected outcome
• – Actual outcome