2.1 Algorithm

Question 1

2.1.1 - Computational thinking

What is abstraction?

Answer 1

• ignoring unnecessary information
• focusing only on the important facts
• simplifies a problem to make it less complex
• program becomes more straightforward to understand the problem and create a solution

Question 2

2.1.1 - Computational thinking

What decomposition?

Answer 2

• breaking a problem down into smaller tasks so that it is easier to solve
• each individual problem can be separately tested and solved
• enables different people to work on the different parts of a larger problem, that can later be recombined to produce a full solution

Question 3

2.1.2 Designing, creating and refining algorithms

What is an algorithm?

Answer 3

• a set of instructions, presented in a logical sequence

Question 4

2.1.2 Designing, creating and refining algorithms

Why do programmers create algorithm design?

Answer 4

• a method of planning a program before writing a code
• considers potential problems of the program
• makes it easier to start creater source code

Question 5

2.1.2 Designing, creating and refining algorithms

What commands does selection use?

Answer 5

• if
• then
• else
• endif

eg:

if firstname == “Steven” then
print(“Hello” + firstname)
elif firstname == “Steve” then
print(“Please use full name”)
else
print(“Who are you?”)
end if

Question 6

2.1.2 Designing, creating and refining algorithms

What commands does iteration use?

with examples

Answer 6

• for loop (for, to, step, next)
• while loop (while, endwhile)
• do while loop (do, until)

Iteration (for loop):
for i = 1 to 10 step 1
input item
next i

Iteration (while loop):
while firstname != “Steven”
firstname = input(“Try again:”)
endwhile

Iteration (do while loop):
do
firstname = input(“Guess name:”)
until firstname == “Steven”

Question 7

2.1.2 Designing, creating and refining algorithms

Flowchart symbols

Answer 7

• start/stop - rectangle with rounded corners
• operation/process - rectangle
• decision (if statement) - diamond
• input/output - parallelogram
• subroutine - rectangle with 2 vertical lines
• direction of flow - arrow