Paper 1 Unit 1

Question 1

What is computational thinking?

Answer 1

A problem solving technique used to investigate and analyse a problem and then develop a solution to it. It helps to make problems more understandable.

Question 2

What are messy problems?

Answer 2

Clusters of interrelated, interdependent complex problems where it is difficult to provide a definitive statement of what the problem is.

Question 3

What is the top-down approach to programming?

Answer 3

A method of analysis that attempts to break down large problem into its smaller component parts.

Question 4

What are the steps of top-down analysis?

Answer 4

The main program is broken down into main component parts. Each component is then broken down into a series of sub-problems. The sub-problems are further broken down until an easily solvable solution is made.

Question 5

What is the bottom-up approach to programming?

Answer 5

A method of finding a solution to a program by solving smaller problems first and integrating them into a larger solution.

Question 6

What are the advantages of using a bottom-up solution?

Answer 6

The smaller parts of the problem are easier to understand. By solving each of the smaller steps it is possible to create a solution to the bigger problem.

Question 7

What is modularisation?

Answer 7

Separating the functional parts of a program into independent modules that can be recombined to create a solution.

Question 8

What are the advantages of modularisation?

Answer 8

The functions (modules) can be allocated to different programmers to speed up the process. Programmers can be allocated to solve those parts of the problem requiring specialist skills. Debugging the elements individually can be more effective.

Question 9

What are the disadvantages of modularisation?

Answer 9

The whole solution must be known in advance. Event-driven programming can ruin the structure of the neat top-down approach.

Question 10

What is debugging?

Answer 10

Locating and fixing errors in a program.

Question 11

What is decomposition?

Answer 11

Breaking down a complex problem into smaller component parts which are easier to understand and solve.

Question 12

What are the advantages of decomposition?

Answer 12

Each sub program can be understood and developed and tested separately.

Question 13

What are the disadvantages of decomposition?

Answer 13

The original problem must be fully understood so a solution can be produced. The sub-problems may not provide a fully functional solution to the original problem.

Question 14

What is pattern recognition?

Answer 14

Looking for patterns or trends to identify potential solutions.

Question 15

Why is using pattern recognition beneficial?

Answer 15

There may be existing solutions for some sub-problems that can be reused. There may be solutions to existing problems that can be modified to help solve the current issue. There may be a group of similar problems that can be fixed with a common core solution which may need to be created or modified.

Question 16

What are the advantages of pattern recognition?

Answer 16

Existing code can be used which has already been tested so the programmer knows it works. It can be modified to add new features which will need to be tested but this is quicker than developing a whole new solution. The same basic code can be developed and reused multiple times but it only needs to be tested once to check it works. The newly created code can be modified to create solutions to similar problems but the main aspects will only need to be tested once. This all saves time and improves reliability.

Question 17

What is abstraction?

Answer 17

The process of extracting the key features of a problem and ignoring the unnecessary detail.

Question 18

What are the advantages of using abstraction?

Answer 18

The programmer can focus on the important aspects of the problem and ignore the non-essential detail. Teams of programmers can work on different aspects of the problem. Programmers can use pre-written or built-in functions without worrying about how they work.

Question 19

What is layering?

Answer 19

Organising a solution into segments that only interact with the previous and following segments.

Question 20

What are the advantages of layering?

Answer 20

Only the detail the programmer needs to solve the problem in their segment is shown for each layer so the path to the solution for the programmer is made less complicated.

Question 21

What are variables?

Answer 21

A value that will change as a result of another action

Question 22

What are constants?

Answer 22

Values that stay the same throughout a program.

Question 23

What are algorithms?

Answer 23

A set of instructions describing the solution to a problem.

Question 24

What must an algorithm include?

Answer 24

Precise instructions to define a problem accurately, all the necessary steps to solve a problem, clear instructions set out in the order they must be followed in and decisions that need to be made, when they need to be made and what happens as a result of them.

Question 25

What are the advantages of algorithms?

Answer 25

They don’t need specialist knowledge to be understood, they provide a detailed break down of a solution, they provide an outline for the coded solution and they are language independent.

Question 26

What are the disadvantages of algorithms?

Answer 26

Some constructs can be difficult to represent, they can be time consuming to create and they can be expressed in several ways which can be confusing for some people.

Question 27

What is a syntax?

Answer 27

The formal structure for a statement.

Question 28

What is a loop?

Answer 28

A sequence of commands that are repeatedly executed until a condition is met.

Question 29

What are flowcharts?

Answer 29

A way of presenting algorithms using diagrams.

Question 30

What are the advantages of flowcharts?

Answer 30

Standard symbols mean they can be understood by everyone and the clear structure makes it easy to see the flow through the program.

Question 31

What are the disadvantages of flowcharts?

Answer 31

They can become very large quite quickly as they use diagrams making complex problems difficult to read and follow. Modifications require a significant amount of work and possibly a redrawing of the whole diagram.

Question 32

What is pseudocode?

Answer 32

A more structured form of English to describe algorithms.

Question 33

What are the advantages of pseudocode?

Answer 33

The structure makes it easy to convert into program code, it can be modified quite easily and it is reasonably easy to follow.

Question 34

What are the disadvantages of pseudocode?

Answer 34

It can be a time consuming process and data can be hard to track throughout it.

Question 35

What is sequence?

Answer 35

Code that executes instructions one after the other.

Question 36

What is selection?

Answer 36

Code is executed based on a previous decision. (if statement)

Question 37

What is iteration?

Answer 37

The code is executed based on whether a condition is met or it is run for a certain number of times.

Question 38

Why should you do a dry run of programs?

Answer 38

To determine what the algorithm does, the output it produces and if there are any errors within it.

Question 39

What is a trace table used for?

Answer 39

A more rigorous way of dry running a program to track the state of variables to check if the program works as expected.