Component 2.1 - Problem Solving

Question 1

What is computational thinking?

Answer 1

Computational thinking is the process involved in taking a complex program, understand the problem and then developing possible solutions. Then representing these solutions in A way that both computers and humans can understand. (E.g. as a set of steps that can be carried out by both a computer and human)

Question 2

What is decomposition?

Answer 2

Decomposition is breaking down a complex program into a series of smaller, more manageable sub problems (e.g. allow for adding money to card > add money on internet, add money in bank > add money at cache machine. and these can be broken up further)

Question 3

What are the advantages of decomposition? (Computational thinking)

Answer 3

• Different people
  can work on different sub problems
• The sub problems are easy to understand and find solutions for unlike the whole problem so a solution can be made faster

Question 4

What is abstraction?

Answer 4

Abstraction is a technique used to reduce something to the simplest set of
characteristics that are most relevant to solving the problem.

Question 5

What are variables used for in computer programming?

Answer 5

In computer programming variables are required to store data that can change

Question 6

What are constants used for in computer programming?

Answer 6

Constants are used in computer programming to store data that does not change.

Question 7

What is a local variable?

Answer 7

A local variable is a variable that is defined within a sub procedure and therefore is only
accessible from within that same sub procedure.

Question 8

What is a global variable?

Answer 8

A global
variable is a variable that has a larger scope as it is defined globally and is therefore
accessible from anywhere within a program.

Question 9

What are the advantages of local variables over global variables?

Answer 9

It is easier to track changes to a local variable and the reasons for those changes than for a global variable, as it is only used within a sub-procedure.

Question 10

What are the advantages of global variables over local variables?

Answer 10

Sometimes a global variable can be the most efficient way of ensuring that an important piece of data is accessible to all sub procedures

Question 11

What are static variables?

Answer 11

Static variables are variables stored in a location in memory and which have a lifespan that lasts the entire time that program is running.

Question 12

What are dynamic variables?

Answer 12

Dynamic variables are variables that each time they are defined, are assigned a new location in memory and have a lifespan that ends when the sub procedure in which it was defined ends.

Question 13

What will good computational thinking skills allow a programmer to do?

Answer 13

Good computational thinking skills will help a programmer to break the problem down into manageable chunks to simplify the solution, and therefore write a successful program

Question 14

Programmers can only write programs for computers to solve if ___

Answer 14

They understand how to solve and the program themselves

Question 15

What are the four key techniques to computational thinking?

Answer 15

Decomposition, pattern recognition, abstraction, algorithms (apparently for wjec we only need to know decomposition and abstraction)

Question 16

What does computational thinking enable you to do?

Answer 16

Computational thinking enables you to work out exactly what to tell the computer to do

Question 17

How can a decomposed program be used to make a working whole program?

Answer 17

The solutions to the sub problems can be brought together to provide a solution to the whole problem

Question 18

What is the disadvantage of decomposition? (Computational thinking)

Answer 18

The solutions to the sub problems may not come together to provide a solution to the whole problem/program

Question 19

Why is abstraction useful?

Answer 19

Abstraction allows the programmer to focus on important aspects of the program rather than fine details, so they can get a working, understandable prototype done quickly.

Question 20

What is pattern recognition? (Computational thinking)

Answer 20

Pattern recognition is looking for similarities among and within problems

Question 21

What is algorithms in computational thinking?

Answer 21

Algorithms is developing a step-by-step solution to the problem, or the rules to follow to solve the problem. (For solving sub problems)

Question 22

What are variable identifiers?

Answer 22

Names

Question 23

What is a self-documenting identifier?

Answer 23

A self documenting identifier is a variable or constant name that implies/reflects what the type of data being stored in it is (e.g. txt_FirstName is a text containing a first name)
All variables should have these

Question 24

What is a local variable’s scope?

Answer 24

A local variable’s scope is the sub procedure (area) from which it is accessible

Question 25

What is the difference between a static and dynamic variable?

Answer 25

Static variables are stored in one location in memory but have a lifespan lasting the entire program. Whereas dynamic variables are stored in a new location in memory each time they are defined and end when the sub procedure they are defined in ends