Q&A – Compare & Contrast Algorithms (Primary 4 – 4CT.04)

Two different algorithms can produce the same outcome.

• True

• False

Answer explanation

True is correct because different algorithms can achieve the same result or output, even if they use different methods or processes to do so.

Which algorithm is better for printing “Hello” 10 times?

• A: OUTPUT "Hello" OUTPUT "Hello" … (10 times)

• B: Repeat 10 times OUTPUT "Hello"

Answer explanation

Choice B is better because it uses a loop to repeat the output, making the code more efficient and easier to manage. Choice A requires writing the output statement 10 times, which is less practical.

The algorithm that produces more stars is:

• Algorithm A

• Algorithm B

• Algorithm C

• Algorithm D

Answer explanation

Algorithm A is the correct choice as it has been shown to produce more stars compared to the other algorithms. Its efficiency and effectiveness in star generation set it apart.

Q4. Editing Algorithms
Task: Printing numbers 1 to 5 can be done using a loop or by writing each print statement separately. Which method is better and why?

• Using a loop, because it is more efficient and concise.

• Writing each print statement separately, because it is clearer.

• Using a loop, because it is slower.

• Writing each print statement separately, because it is faster.

Answer explanation

Using a loop is better because it allows for more efficient and concise code. It reduces repetition and makes it easier to modify the range of numbers printed, enhancing maintainability compared to writing separate print statements.

The best algorithm is always the shortest one.

• True

• False

Answer explanation

The statement is false because the best algorithm is not always the shortest one. Factors like efficiency, scalability, and clarity also matter. A longer algorithm can be more effective in certain contexts.

Which algorithm is more suited for checking if a number is even?

• IF number MOD 2 == 0 THEN OUTPUT "Even" ELSE OUTPUT "Odd"

• OUTPUT "Even"

Answer explanation

The correct choice uses a conditional statement to check if the number is even by evaluating 'number MOD 2 == 0'. This provides a clear output of 'Even' or 'Odd', making it the most suitable algorithm for this task.

To move a robot forward 10 steps, which command should be used?

• Move forward 10 steps

• Turn left 10 steps

• Move backward 10 steps

• Jump 10 steps

Answer explanation

The command 'Move forward 10 steps' directly instructs the robot to move in the desired direction and distance. The other options do not achieve the goal of moving forward.

Which is more suited if the wall is not always 10 steps away?

• Repeat 10 times Move forward

• Repeat until wall reached Move forward

Answer explanation

The correct choice is 'Repeat until wall reached, Move forward' because it allows for dynamic adjustment based on the wall's distance, unlike 'Repeat 10 times' which assumes a fixed distance.

Task: Clap 4 times. Which algorithm is correct?

• Repeat 4 times OUTPUT "Clap"

• Repeat 5 times OUTPUT "Clap"

Answer explanation

The task requires clapping 4 times. The correct algorithm is 'Repeat 4 times OUTPUT "Clap"' as it matches the specified number of claps. The other option incorrectly repeats 5 times.

The best option is:

• Option A

• Option B

Answer explanation

Option B is the correct choice because it aligns best with the criteria outlined in the question, demonstrating a more suitable solution compared to Option A.