Unit 1 - Computational Thinking

Question 1

What are errors?

Answer 1

An error is something that disrupts the program or occurs unintentionally within it, it can also cause an unwanted outcome in the program even if it still runs

Question 2

What are three types of errors

Answer 2

Syntax Error
Runtime Error
Logic Error

Question 3

What is a syntax error?

Answer 3

This is a grammatical error in the code, it can be caused by things such as a missing bracket, colon or a misspelled word

Question 4

What is a runtime error?

Answer 4

This is something that stops the code whilst it is running or prevents it from running all together

Question 5

What is a broke error?

Answer 5

This occurs when a program is running and is asked to perform an impossible task such as multiplying something by zero

Question 6

What is a logic error?

Answer 6

This occurs when there is a fault in the logic or structure of the program - it does not usually cause the program to stop completely but it can cause an unexpected result from the computer

Question 7

Where did the term ‘computer bug’ get its name?

Answer 7

In 1947 a group of computer scientists noticed unexpected results coming from their machines, they found that it was due to a moth trapped inside of a one machine and they were forced to literally ‘debug’ the machines

Question 8

What is a trace table?

Answer 8

A black table into which you can input the results of a program each time you run through it

Question 9

Why are trace tables helpful?

Answer 9

They allow us to predict the results of a programme and identify errors in it without actually running it

Question 10

Why are flowcharts helpful?

Answer 10

They allow programmers to see the distinct steps which need to be carried out in order to reach a desired outcome and layout the structure of the code

Question 11

What pseudocode?

Answer 11

Pseudocode is a cross between a programming language such as python and English

Question 12

Why is pseudocode useful?

Answer 12

It can be understood by most people even if they do not understand coding so we can communicate complicated concepts effectively

Question 13

Why do you need to be careful when using pseudocode?

Answer 13

Everyone writes pseudocode differently but you need to ensure that your rules are consistent throughout .e.g. you cannot decide that all variables are written in capitals halfway through

Question 14

Why are search algorithms used?

Answer 14

They enable a program to identify a specific value in an array easily

Question 15

Explain how the binary search algorithm works

Answer 15

1. The array must be sorted in ascending numerical order
2. Identify the midpoint
3. If Midpoint = Required Index, print
4. If Midpoint > Required Index THEN End Of Array = Midpoint -1
5. If Midpoint < Required Index THEN Start Of Array = Midpoint +1
6. Go back to step two and LOOP until Required Index is identified

Question 16

State one advantage and three disadvantages of the binary search search algorithm

Answer 16

Advantages:
1. Quicker for longer arrays and more efficient than a linear search
Disadvantages:
1. It is harder to program
2. It takes time to reorder it if an item is removed or added
3. It requires the array to be sorted

Question 17

Explain how the linear search algorithm works

Answer 17

The computer will iterate through each item in the array until it identified the required index

Question 18

State three advantages and two disadvantages of the linear search algorithm

Answer 18

Advantages:
1. Does not require items to be sorted therefore saves time
2. It is not affected by insertions or deletions
3. Works quicker on small lists, especially on today’s computers
Disadvantages:
1. Takes a long time on larger arrays
2. The item may be one of the last ones in the list

Question 19

Describe the bubble sort algorithm

Answer 19

Two items in an array are compared, if the first is larger than the second they are swapped so that they are in ascending numerical order; the program then iterates through the array multiple times in order to sort every number into the same order

Question 20

Describe the merge sort algorithm

Answer 20

The array is split into couplets, if those two numbers are not in ascending numerical order they are switched. They are then merged with another couplet and the same process repeats so that the whole array is combined again and in ascending numerical order

Question 21

What are operators?

Answer 21

Built in commands in python that allow us to perform specific function

Question 22

What are the three types of operator?

Answer 22

Logical, relation and arithmetic