1 Understanding Algorithms

Question 1

What is an algorithm?

Answer 1

• Step-by-step instructions in how to solve a problem/ how to carry out a task
• A specific accurate solution to a problem
• A detailed design for a solution

Question 2

Characteristics of an algorithm

Answer 2

• A solution to a problem
• Unambiguous
• Sequence of steps
• It can be used again
• It will provide the same result as long as the input is the same

Example:
Making coffee
* Pour 1 liter of coffee (Give clear, unambiguous instructions)
* Heat the water and turn off when appropriate (Unclear, ambiguous)

Question 3

What is a successful algorithm?

Answer 3

A successful algorithm fulfills these three points.
* Accuracy - it leads to the expected outcome
* Consistency - it produces the same result each time it is run
* Efficiency - it solves problem in shortest possible time using fewest possible computer resources

Question 4

Difference between algorithm and program

Answer 4

• Algorithm - a detailed design of a solution to a particular problem
• Program - A way of implementing that design

Question 5

Implementations of algorithms

Answer 5

• Written description
• Pseudocode
• Flowchart
• Program code

Question 6

What does a diamond shape represent in a flowchart?

Answer 6

*Selection
* indicates a decision to be made
* It produces True/False leading to two possible outcomes

Question 7

What does a skew shape represent in a flowchart?

Answer 7

Input/output

Question 8

What does an arrow shape represent in a flowchart?

Answer 8

• Logical flow of the algorithm
• It shows what steps to be taken next

Question 9

What does a rounded rectangle shape represent in a flowchart?

Answer 9

• Start/end
• Terminal

Question 10

What does a rectangle shape represent in a flowchart?

Answer 10

• Process
• Indicates a process to be carried out

Question 11

Flowchart

Answer 11

• A diagram of implementation of algorithm
• Provides more visual display

Question 12

Pseudocode

Answer 12

• A structed, code-like language that can be used to describe an algorithm
• Is relatively straightforward to translate into any high-level programming language
• helps to focus on the logic and efficiency of the algorithm (without having to bother about the rules of any particular programming language)

Question 13

Variable

Answer 13

• A container that stores data(value)
• The value in a variable is not fixed
• Variable can store different values during the course of a program and each time a program is run

Question 14

Constant

Answer 14

A container that holds a value that never changes
* Pi value
* Number of m in km

Question 15

Identifier

Answer 15

• A unique name given to a variable or a constant
• Using descriptive names can improve readability

Question 16

Types of naming convention

Answer 16

• snake_case
• camelCase/CamelCase

Question 17

Variable and constant

Answer 17

• both hold/store a value
• both have unique identifier
• Value in variable is not fixed while value in constant is

Question 18

Why is a variable useful?

Answer 18

• The value in variable can change as a program is running
• Variables let the same program to process different sets of data

Question 19

Operator

Answer 19

A character that represents an action

Question 20

Arithmetic operators

Answer 20

7 types
* Addition (+)
* Subtraction (-)
* Multiplication (*)
* Real division(/) - includes decimal places
* Quotient(DIV) - return whole number
* Modulus(MOD) - return the remainder
* Exponentiation(^) - power of