Algorithms 2.1

Question 1

Define Computational Thinking

Answer 1

The thought processes involved in formulating a problem and expressing its solution(s) in such a way that a computer—human or machine—can effectively carry out.

Question 2

Give 2 examples of computational thinking

Answer 2

Could be solving a jigsaw puzzle or playing with lego.

Question 3

Define abstraction

Answer 3

Removing unnecessary details and keeping only relevant ones.

Question 4

Give an example of abstraction

Answer 4

Sat-nav

Question 5

Define decomposition

Answer 5

The process by which a complex problem or system is broken down into parts that are easier to conceive, understand, program and maintain

Question 6

Give an example of decomposition

Answer 6

Getting to school

Question 7

Define algorithmic thinking and give an example

Answer 7

A way of getting to a solution by identifying the steps needed. An example of this is solving a math problem.

Question 8

Define a syntax error and identify an example of one in programming.

Answer 8

An input by the programmer/user that does not comply with the laws of that programming language. e.g. pRint(). To fix them just change the statement so it follows these laws.

Question 9

Define a logic error and identify an example of one in programming.

Answer 9

An error in the program that does not stop the program but produces an unexpected output. An example of this could be using + instead of - or using // instead of /.

Question 10

Terminal symbol and its purpose

Answer 10

An oval - indicates the beginning and end of a program.

Question 11

Input/output symbol and its purpose

Answer 11

A parallelogram - identifies any input needed and when output is displayed.

Question 12

Process symbol and its purpose

Answer 12

A rectangle - marks when a calculation or a process is carried out.

Question 13

Subroutine symbol and its purpose

Answer 13

a rectangle with tramlines at either ends - used when a subroutine is needed that is not part of the main program.

Question 14

A decision symbol and its purpose

Answer 14

a rhombus - acts as an if statement in the program.

Question 15

line symbol and its purpose

Answer 15

An arrow - shows the direction of code flow.

Question 16

Step by step how to complete a trace table

Answer 16

Create a column of each variable in the program and any inputs and outputs. When the state of a variable changes, mark that value in a new row under that column and mark and output taken. Work through the program like a computer would do until the program ends. This allows you to check for any logic errors in your program.

Question 17

Define a trace table

Answer 17

A technique used to test algorithms, in order to make sure that no logical errors occur while the algorithm is being processed.

Question 18

How to identify an input

Answer 18

look in the program for an input statement showing what data type it is and what input message is being displayed.

Question 19

How to identify a process

Answer 19

see if the variable name for an input or a value changes in the program. This is usually a calculation.

Question 20

How to identify an output

Answer 20

look for a statement that includes the following:

print()
output
return