Topic 1 : Computational Thinking

Algorithm

A precise method for solving a problem

Decomposition

Breaking down a problem into smaller, more manageable sub programs which then make it easier to solve.

Benefits of decomposition

1. Reduces complexity

2. Different sub programs can be worked on simultaneously

3. Each sub program can be isolated and tested individually

4. Sub programs often lead to the creation of independent, reusable codes

Examples of decomposition irl

Video game design:

Decomposed into individual layers (character mechanics, world landscape design, sound engineering etc)

Abstraction

The process of removing or hiding unnecessary information so only the important details remain.

Benefits of abstraction

1. Reduces complexity

2. Prevents information overload

3. Saves time and resources

Examples of abstraction irl

London Underground map:

Only shows what a commuter needs, and omits unnecessary details

Flow chart

A graphical representation of an algorithm

Flow Chart Symbols

DIV (//)

Quotient ( only returns whole number)

MOD (%)

Modulo/Modulus ( Only returns remainder)

**/^

exponentiation ( To the power of)

Variable

A named location in computer memory that stores a value that can change

Constant

A named location in computer memory that stores a value that cannot change

Syntax error

An error that breaks the grammatical rules of a programming language and stops it from running

Examples

1. Typos and spelling errors

2. Incorrect use of operators

3. Invalid variable or function names

Logic error

Incorrect correct code is used. Program still runs but produces incorrect output as a result

Examples

1. Infinite loops

2. Incorrect use of operators

3. Using variables before they are assigned

Runtime error

An error that causes the program to crash

Examples

1. Dividing a number by 0

2. Index out of range of an array

3. Unable to read or write a drive

Relational Operators

1. Equal to

2. Not equal to

3. Less than

4. Less than I'd equal to

5. Greater than

6. Greater than or equal to

Equal to

==

Not equal to

!=

Less than

<

Less than or equal to

Greater than

>

Greater than or equal to

>=

Logical operators

1. And

2. Or

3. Not

( logical operators are always used alongside relational operators to form a comparison)

Not Gate

Input is always opposite to output

Eg: Input (A)

Output (Not A)

And Gate

Both Inputs have to be on in order for output to be in

Eg: Input (1,1) Input (0,1)

Output (1) Output (0)

Or gate

Only one input must be on for output to be on

Eg: Input (0,0) Input (0,1)

Output (0) Output (1)

Truth Table Structure

Input columns/Output columns