SLR 2.2 Programming Techniques

Question 1

What is iteration?

Answer 1

‘iteration’ is repeating the same code more than once (looping).

Iteration is one of three main constructs in programming

Question 2

What type of programming construct is demonstrated by the following pseudocode:

for i=0 to 7
print(i)
next i

Answer 2

This is an example of iteration

Question 3

How many times would the following pseudocode print?

for i=0 to 7
print(i)
next i

Answer 3

8 times - 0 1 2 3 4 5 6 7

Question 4

What would the following pseudocode do?

for i=0 to 7
print(i)
next i

Answer 4

it would print the numbers 0 1 2 3 4 5 6 7

Question 5

Which programming construct is shown by the following pseudocode?

if entry == ”a” then
    print(“You selected A”)
elseif entry == ”b” then
    print(“You selected B”)
else
    print(“Unrecognised selection”)
endif

Answer 5

This is an example of selection

Question 6

Which programming construct is shown by the following pseudocode?

while answer!=”computer”
answer=input(“What is the password?”)
endwhile

Answer 6

This is an example of iteration

Question 7

What does the following pseudocode do?

while answer != ”computer”
answer=input(“What is the password?”)
endwhile

Answer 7

repeatedly asks the user to input the password until they enter “computer”

Question 8

Is the user automatically shown the request for the password to be entered?

while answer != ”computer”
answer=input(“What is the password?”)
endwhile

Answer 8

no - if the variable answer is already == “computer” then the request is not shown.

Question 9

What is the condition to trigger the request for the password to be entered?

while answer != ”computer”
answer=input(“What is the password?”)
endwhile

Answer 9

if the variable answer is not equal to “computer”

Question 10

What is sequence?

Answer 10

‘sequence’ is about the ordering of the steps in an algorithm.

sequence is one of 3 main constructs in programming.

Question 11

Which programming construct is shown by the following pseudocode?

print(“Welcome to my program”)
username = input(“What is your username?”)
password = input(“What is your password?”)

Answer 11

sequence

Question 12

What is an integer?

Answer 12

A data type that represents whole number values

Question 13

What is a real?

Answer 13

A data type that represents number values that contain decimal points

Question 14

What is a Boolean?

Answer 14

A data type that represents only True or False (these are sometimes used to represent on/off or yes/no)

Question 15

What does alphanumeric mean?

Answer 15

Either a letter or a number

Question 16

What is a character?

Answer 16

A single alphanumeric value or a symbol (e.g. ! , ? # & etc.)

Question 17

What is a string?

Answer 17

A series of characters (alphanumeric or symbols) e.g. a sentence or word.

Question 18

What is an array?

Answer 18

A set of data items of the same type grouped together using a single identifier. Each of the data items is addressed by the variable name and an index e.g. my_index[3] would access the fourth item in the array.

Question 19

What is a record?

Answer 19

A data structure which consists of a collection of elements, typically in fixed number and sequence and typically indexed by names. The elements of records may also be called fields.

Question 20

What is selection?

Answer 20

One of the 3 basic programming constructs where a Boolean expression is analysed and the code executed depends on the result of the anaylsis.

Question 21

What is branching?

Answer 21

It is another name for selection - it is when the code executed depends on a Boolean expression being analysed and the result of the analysis directs what code is executed.

Question 22

What is a global variable?

Answer 22

A global variable is one which can be used anywhere in a program

Question 23

What is a local variable?

Answer 23

A local variable is one which is defined and can only be used within one part of a program (usually a function or procedure)

Question 24

What is modularity?

Answer 24

Modularity is building code in a modular way (in sections).

Question 25

Give three reasons why a modular approach to coding is a good idea

Answer 25

It allows the task of coding to be split between a team of people, it allows code to be reused (thus shortening the amount of code and thus the time needed to produce it), it is easier to maintain as the code is in one place and reused not repeated throughout the program

Question 26

What is a module?

Answer 26

A block of code that is reused

Question 27

What is a procedure?

Answer 27

A module of code that may or may not take parameters but which does not return a value. The procedure should carry out one task or action that is clearly indicated by its name.

Question 28

What is a function?

Answer 28

A module of code that may or may not take parameters and which returns a value. The function should carry out one task or action that is clearly indicated by its name.

Question 29

What is a parameter?

Answer 29

A value (or data structure containing a set of values) that are passed to a module of code when it is called.

Question 30

List the key words for SQL you need to know for GCSE

Answer 30

SELECT, FROM, WHERE, LIKE, AND, OR

Question 31

In an SQL search how is an asterisk (*) used?

Answer 31

An asterisk (*) is used to select all fields e.g.
SELECT * FROM customers WHERE customer_id = 1

Question 32

In an SQL search how is a percent sign (%) used?

Answer 32

A percent sign (%) is used as a wildcard (to match anything) e.g.
SELECT name, address FROM customers WHERE customer_name LIKE ‘J%’
This would show the name and address of all customers whose name starts with J

Question 33

What is the difference between a for loop and a while loop?

Answer 33

A for loop will execute a fixed number of times e.g. For x in range(0, 5) will execute 5 times. This is count controlled iteration.
A while loop will execute until the Boolean expression it is based on evaluates to False e.g. While goals < 10 will execute until goals is not less than 10. This is condition controlled iteration.