Algorithms

Question 1

State what is meant by the term ‘algorithm’.

Answer 1

A step-by-step description of how to solve a problem/carry out a task

Question 2

Give examples of some implementations of algorithms.

Answer 2

• Flowcharts
• Pseudocode
• Written descriptions
• Program code

Question 3

What are the three main programming constructs used within an algorithm?

Answer 3

• Sequence
• Selection
• Iteration

Question 4

What does this symbol represent in a flowchart?

Answer 4

Selection - shows true/false decisions where there are two possible outcomes

Question 5

What does this symbol represent in a flowchart?

Answer 5

Input / Output - shows when data is input or output by the algorithm

Question 6

What does this symbol represent in a flowchart?

Answer 6

Subprogram - shows function or procedure that has its own flowchart

Question 7

What does this symbol represent in a flowchart?

Answer 7

Terminal - shows start and end of an algorithm

Question 8

What does this symbol represent in a flowchart?

Answer 8

Process - shows data processing (e.g. a calculation)

Question 9

What is a subprogram?

Answer 9

A self-contained block of code that performs a specific task within a larger program

Question 10

Give some reasons as to why the use of a subprogram is beneficial.

Answer 10

• Breaks down complex program into smaller parts
• Makes program logic clearer
• Makes it easier to maintain code
• Enables code to be used as many times as needed in program
• Enables code used for common tasks to be stored in libraries and used in different programs
• Helps efficiency of a team of programmers working on project at same time