Computational thinking

Computational thinking

​Computational thinking

​Computational thinking involves taking that complex problem and breaking it down into a series of small, more manageable problems (decomposition).

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Each of these smaller problems can then be looked at individually, considering how similar problems have been solved previously and focusing only on the important details, while ignoring irrelevant information (abstraction).

​

Next, simple steps or rules to solve each of the smaller problems can be designed (algorithmic thinking).

Decomposition

​Breaking a problem down

This is when we break a larger problem down into smaller more manageable tasks

Abstraction

​Ignoring / removing

This is when we remove or ignore the bits that are not important to solving the problem.

For​ example, when they created an underground tube they chose to ignore buildings and trees

Algorithmic thinking

Solution to problem

Once we have used decomposition and abstraction to a problem, we start to develop a solution with flowcharts and pseudocode

Open Ended

What are the 3 concepts of computational thinking?

Open Ended

What is Decomposition?

Open Ended

What is abstraction?

Open Ended

What is algorithmic thinking?

We can show the solution to a problem with a flowchart

​Some text here about the topic of discussion.

Algor​ithms:

​Flowcharts

We can show the solution to a problem written instructions - pseudocode

​Some text here about the topic of discussion.

Algor​ithms:

​Pseudocode

​Algorithm constructs

Algorithms are designed using common building blocks. These building blocks form the basis for all programs.

​

There are three basic building blocks to consider:

• sequence is the order in which instructions occur and are processed

• selection determines which path a program takes when it is running

• iteration is the repeated execution of a section of code when a program is runningm

Multiple Select

There are 3 basic programming constructs, select them from below:

• Decomposition

• Sequence

• Abstraction

• Selection

• Iteration

​Sequence

​Sequence is the order in which programming statements are executed. Programming statements usually run one after another in order, unless one of the other programming constructs is used.

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The sequence of a program is extremely important as once these are translated, carrying out instructions in the wrong order leads to a program performing incorrectly.

​Sequence

​Here is an example of a program that uses sequence, the lines of code are ordered

​Sequence

​Here is an example of a program that uses sequence, the arrows show the direction on the sequence

​Selection

​Selection is a programming construct where a section of code is run only if a condition is met. In programming, there are occasions when a decision needs to be made. Selection is the process of making a decision. The result of the decision determines which path the program will take next.

For example, a program could tell a user whether they are old enough to learn how to drive a car. If the user's age meets the required driving age, the program would follow one path and execute one set of statements. Otherwise, it would follow a different path and execute a different set of statements.

​Selection

​Here is an example of selection.

​In Python we would use:

​if .........

​elif

​else

​Selection

​Here is an example of selection.

In flowcharts selection is represented as a decision, this is a diamond shape that has a Yes/True and No/False outcome

​Iteration

​There are times when a program needs to repeat certain steps until told otherwise, or until a condition has been met. This process is known as iteration.

Iteration is often referred to as looping, since the program ‘loops’ back to an earlier line of code. Iteration is also known as repetition.

Iteration allows programmers to simplify a program and make it more efficient . Instead of writing out the same lines of code again and again, a programmer can write a section of code once, and ask the program to execute the same line repeatedly until no longer needed.

​Iteration

​Here is an example of using Iteration, in this case we are using a 'while' loop that will continue to print 'Hello World' until the count gets to 3

​Iteration

​Here is an example of using Iteration, in this case we are using a 'while' loop that will continue to print 'Looping' until the count gets to 9

Multiple Choice

Which of the 3 programming constructs is being used here?

• Selection

• Sequence

• Iteration

• Decomposition

Multiple Choice

Which of the 3 programming constructs is being used here?

• Selection

• Sequence

• Iteration

• Decomposition

Multiple Choice

Which of the 3 programming constructs is being used here?

• Selection

• Sequence

• Iteration

• Decomposition

Open Ended

What is Computational thinking?

Multiple Choice

The table to the left contains several definitions of terms that are used in Computer Science.

Select the letter of the definition that matches the keyword 'decomposition'

• A

• B

• F

• D

• E

Multiple Choice

The table to the left contains several definitions of terms that are used in Computer Science.

Select the letter of the definition that matches the keyword 'Abstraction'

• A

• B

• F

• D

• E

Multiple Choice

The table to the left contains several definitions of terms that are used in Computer Science.

Select the letter of the definition that matches the keyword 'casting'

• A

• B

• F

• D

• E

Multiple Select

A programmer has written an algorithm to outpur a series of numbers. The algorithm is shown to the left.

Identify TWO basic programming constructs that have been used in this algorithm

• Sequence

• Iteration

• Selection

• Casting

​Data Types

​Data is classified into types, such as a set of whole numbers (also known as integers) or a set of printing characters.

​

Different types of data are represented in different ways inside a computer and need varying amounts of memory to store them.

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They also have different operations that can be performed upon them. All values that belong to the same data type will be represented in the same way.

​The most commonly supported data types in programming languages are:

​

Multiple Choice

Which of the following is of the data type STRING

• "Hello"

• Yes / No

• "A"

• 7

• 9.65

Multiple Choice

Which of the following is of the data type FLOATING POINT (FLOAT)

• "Hello"

• Yes / No

• "A"

• 7

• 9.65

Multiple Choice

Which of the following is of the data type BOOLEAN

• "Hello"

• Yes / No

• "A"

• 7

• 9.65

Multiple Choice

Which of the following is of the data type CHARACTER

• "Hello"

• Yes / No

• "A"

• 7

• 9.65

​Variables

​Variables are data values that can change when the user is asked a question, for example, their age. Variables may change during program execution.

A variable is a memory location. It has a name that is associated with that location. The memory location is used to hold data. The key difference when comparing a constant to a variable is that the value associated with a variable name may change during program execution. For example 'highScore' would need to be variable to change throughout a game.

​Variables

​As you can see, variables are the names of the location, each variable stores a value. The value will be stored as a data type

Multiple Choice

What is the variable name that holds the value "TechVidvan"?

• Name

• num

• name

• seq

Multiple Choice

What is the variable name that holds the value 35453?

• Name

• num

• name

• seq

Multiple Choice

What is the data type of the value that is stored in the variable called name?

• string

• int

• list

• boolean

Multiple Choice

What is the data type of the value that is stored in the variable called num?

• string

• int

• list

• boolean

Multiple Choice

What is the data type of the value that is stored in the variable called seq?

• string

• int

• list

• boolean

Multiple Choice

Here is a variable that will hold the users name. What data type will this value be set as?

• string

• int

• boolean

• character

Open Ended

Type a pseudocode statement to assign the value 7.3 to a variable with the identifier timer

Multiple Choice

Select the most appropriate data type for the variable timer

• Float

• Integer

• String

• Boolean

Multiple Choice

Heath is researching how long, to the nearest minute, each student in his class spends laying computer games in 1 week. He is storing the data in a 2D array.

Select the data type that could be used to store the number of minutes in this array

• String

• Float

• Integer

• Boolean

Open Ended

State why this data type is the most appropriate

Multiple Choice

When customers pay using a card such as the one to the left, shops use computer systems to process the payment. Select the most appropriate data type for the amount paid

• Date

• Integer

• Real/Float

• String

Multiple Choice

When customers pay using a card such as the one to the left, shops use computer systems to process the payment. Select the most appropriate data type for the customers card number

• Date

• Integer

• Real/Float

• String

Multiple Choice

When customers pay using a card such as the one to the left, shops use computer systems to process the payment. Select the most appropriate data type for when the payment is made

• Date

• Integer

• Real/Float

• String

​Casting

​There may be times when you want to specify a type on to a variable. This can be done with casting.

• int() - constructs an integer number

• float() - constructs a float number

• str() - constructs a string

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Open Ended

Louise writes a program to work out is a number entered by the user is odd or even. Her first attempt is shown to the left.

The program contains a syntax error on line 05

State what is meant by a syntax error

Open Ended

Louise writes a program to work out is a number entered by the user is odd or even. Her first attempt is shown to the left.

The program contains a syntax error on line 05

Give a corrected version of line 05 that fixes the syntax error

Open Ended

A program needs to perform the following tasks:

Input two numbers from the user

Compare both numbers and output the largest number

Type the algorithm for this program: