Nancyvarkey at 05:49, 21 June 2021

2021-06-21T05:49:04Z

Pravin1389 at 05:37, 2 February 2021

2021-02-02T05:37:14Z

Pravin1389 at 05:36, 2 February 2021

2021-02-02T05:36:08Z

Nancyvarkey at 16:08, 24 January 2021

2021-01-24T16:08:43Z

Nancyvarkey at 16:00, 24 January 2021

2021-01-24T16:00:47Z

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Kr.jayesh: Created page with "Title of the script: Control-Flow Author: Jayesh Katta Ramalingaiah Domain Reviewer: Novice Reviewer: Keywords: Rust, variables, if, else, else if, conditions {| borde..."

2021-01-14T19:18:02Z

Created page with "Title of the script: Control-Flow Author: Jayesh Katta Ramalingaiah Domain Reviewer: Novice Reviewer: Keywords: Rust, variables, if, else, else if, conditions {| borde..."

New page

Title of the script: Control-Flow

Author: Jayesh Katta Ramalingaiah

Domain Reviewer:

Novice Reviewer:

Keywords: Rust, variables, if, else, else if, conditions

{| border = “1”
|| <center>'''Visual Cue'''</center>
|| <center>'''Narration'''</center>

|-
|| Slide: Title
|| Welcome to the spoken tutorial on “'''Control-Flow '''in''' Rust'''”.

|-
|| Slide:

Learning Objectives
|| In this tutorial, we will learn about the:

* '''if/else control flow statements'''
* Different '''types''' of '''loops'''
* '''Syntax''' of all the '''control flow statements '''and their usage

|-
|| Slide: System Specifications
|| This tutorial is recorded using:

* '''Ubuntu Linux''' OS version 18.04
* '''Rust''' version 1.47.0
* '''Visual Studio Code''' version 1.45.0 ('''code editor''')

However you may use any other '''editor''' of your choice.

|-
|| Slide : Pre-requisites
|| To practice this tutorial,

* You should be familiar with '''compiling''' and '''running Rust''' files'''.'''
* If not, please go through the prerequisite '''Rust''' tutorials on this website.

|-
|| Slide: Code files
||
* The files used in this tutorial are available in the''' Code files''' link on this tutorial page.
* Pls download and extract the file.
* Make a copy and then use it for practising.

|-
|| Slide: Control Flow
||
* '''Control flow''' means deciding whether to run a piece of code, based on a '''condition.'''
* This is an integral part of any '''programming language'''.
* This can be achieved using '''if''' and '''else statements'''

|-
|| Slide: Control Flow

<nowiki>[Highlight]: </nowiki>'''if expressions'''
||
* '''if''' is the most common way to handle the '''flow''' of our code.

|-
|| Slide: Control Flow

<nowiki>[Highlight]: </nowiki>'''else if'''
||
* We can use '''else if, '''if there are multiple '''conditions''' to be evaluated.

|-
|| Slide: Control Flow -1

||
* We can use '''if''' without '''else''', however '''else''' cannot be used without '''if'''.
* '''else''' is always preceded with an '''if statement'''.

|-
|| Slide: Control Flow -2
||
* Also, we can use one or more '''else if''' along with the''' if statement.'''
* Ensure that when you use''' else if, '''always follow it up with an '''else condition''' too.
* The code works fine even when we don’t end with an '''else statement.'''
* However, to maintain '''coding standards''' it is advised to use '''else condition''' when we are using '''else if'''

Let us understand all this by using an example.

|-
|| Press '''Ctrl+Alt+T '''keys
|| Open the '''terminal''' by pressing '''Ctrl,Alt''' and '''T''' keys simultaneously on the keyboard.

Ensure that you have '''root permissions''' to '''run''' the '''commands'''.

|-
|| Only Narration
|| Here onwards, please remember to press the '''Enter''' key after typing each '''command'''.

|-
|| <nowiki>[Terminal] Type:</nowiki>

cd Desktop/MyRustProject

<nowiki>[Enter]</nowiki>
|| Using '''cd command''' go to the '''Rust''' practice folder which we created earlier.

|-
|| <nowiki>[Terminal] Type:</nowiki>

cargo new '''control_flow'''

<nowiki>[Enter]</nowiki>
|| Let us create a new '''project''' named '''controlFlow.'''

Type the '''command''' as shown.

|-
|| Open Visual Studio Code editor.
|| You may use any '''editor''' of your choice.

I will use '''Visual Studio Code editor '''for this demonstration'''.'''

|-
|| <nowiki>[Editor] </nowiki>

Welcome Page ->

Open Folder ->

'''control_flow'''
|| Open the created '''project''' by clicking on the '''Open folder''' link in the '''Welcome page.'''

Browse and locate the folder “'''control_flow'''”.

Then click on the '''OK '''button at the top right corner.

|-
|| <nowiki>[Editor] </nowiki>

Click on '''control_flow'''
|| Under the '''EXPLORER''' section, expand the '''project''' folder “'''controlFlow'''” by clicking on it.

|-
|| <nowiki>[Editor] </nowiki>Expand '''src '''and click on '''main.rs'''
|| Then expand '''src''' and open the''' main.rs''' file.

|-
|| <nowiki>[Editor] Type: </nowiki>

fn main(){

let a = 30;

let b = 20;

if a>b{

println!(“A is greater than B”);

} else {

println!(“B is greater than A”);

}

}
|| In the '''editor''', replace the '''code''' as shown.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''If a>b'''
|| Here we are checking whether the '''condition a''' is greater than '''b''' or not.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''println!(“A is greater than B”);'''
|| When the '''condition''' is satisfied, the '''print statement''' inside the '''if block''' gets printed.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''else {'''

'''println!(“B is greater than A”);'''

'''}'''
|| If not, the '''print statement''' in the '''else block''' gets executed.

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

cd '''control_flow'''<nowiki>[Enter]</nowiki>
|| Go to the '''project''' folder '''controlFlow '''using the '''cd command.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| Now type '''cargo run.'''

|-
|| <nowiki>[Terminal] Highlight:</nowiki>

'''A is greater than B'''
|| The '''print statement''' in the '''if block''' is executed and printed, as the '''condition''' is satisfied.

|-
|| Switch to Editor
|| Switch back to the '''editor.'''

|-
|| <nowiki>[Editor] Modify: </nowiki>

fn main(){

let marks = 50;

if marks>35{

println!(“You are qualified!”);

}

}
|| In the '''editor''', modify the '''code''' as shown.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

i'''f(marks>35){'''

'''println!(“You are qualified!”);'''

'''}'''
|| Here, in this example, we are considering only the '''if condition'''.

When the '''condition''' gets satisfied, the '''block''' gets executed.

If not, then nothing is printed.

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch back to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| '''Run''' the '''project'''.

|-
|| <nowiki>[Terminal] Highlight:</nowiki>

'''You are qualified!'''
|| As the '''condition (marks greater than 35)''' is satisfied, the '''block''' gets executed.

Here, we emphasise that only an '''if condition''' can exist without an '''else statement.'''

|-
|| Switch to Editor
|| Switch back to the '''editor.'''

|-
|| <nowiki>[Editor] Modify: </nowiki>

fn main(){

let a = 5;

if a%2 == 0{

println!(“Number is divisible by 2”);

} else if a%3 == 0{

println!(“Number is divisible by 3”);

} else {

println!(“Number is not divisible by 2 and 3”);

}

}
|| In the '''editor''', let’s update the '''code''' as shown.

This is the '''if-elseif-else statement'''.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''if a%2 == 0{'''

'''println!(“Number is divisible by 2”);'''

'''}'''
|| Here, we are checking a '''condition if a % 2 == 0''' or not.

When this '''condition''' is satisfied, the''' if block''' gets executed.

When this '''condition''' fails, the '''else if block '''is checked'''.'''

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''else if a%3 == 0{'''

'''println!(“Number is divisible by 3”);'''

'''}'''
|| '''else if block''' checks the '''condition if a % 3 == 0''' or not.

When this '''condition''' is satisfied, the '''else if block''' gets executed.

When this '''condition''' also fails, the '''else block '''is executed.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''else {'''

'''println!(“Number is not divisible by 2 and 3”);'''

'''}'''
|| And prints this message as the above two '''conditions''' are not satisfied.

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch back to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| Now type '''cargo run.'''

|-
|| <nowiki>[Terminal] Highlight:</nowiki>

'''Number is not divisible by 2 and 3'''
|| See the output.

'''Number is not divisible by 2 and 3 '''is printed because the above two '''conditions''' are not satisfied.

|-
|| Only narration
|| That’s how the '''if-else if-else statements''' work in '''Rust'''.

|-
||
|| Next, let’s learn about '''loops'''.

|-
|| Slide: Control Flow - Loops
||
* '''Loops''' are '''control structures''' that are repeatedly executed until a particular '''condition''' fails.
* That means, '''loops''' repeat a '''block''' of code '''n''' number of times until a particular '''condition '''fails.

|-
|| Slide: Control Flow - Loops
||
* There are two '''types''' of '''loops''' supported in '''Rust'''
** '''For loop''' and
** '''While loop'''
* Note: There is no''' do while loop''' in '''Rust'''

|-
|| Only Narration
|| Let us take an example and understand '''Loops''' better.

|-
|| <nowiki>[Editor] Type: </nowiki>

fn main(){

loop {

println!(“Hello World!”);

}

}
|| Go back to the '''editor''' and replace the '''code''' as shown.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''loop '''
|| '''loop''' is a '''keyword''' in '''Rust''' which iterates a '''block''' until it fails.

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| Now type '''cargo run.'''

|-
|| <nowiki>[Terminal] </nowiki>Show:

'''Hello world'''

''(being printed infinite times)''
|| We can see '''Hello World''' being printed infinite times, until the '''memory''' in the '''stack''' ends.

This is an '''infinite loop'''.

|-
|| Only Narration
|| Press '''Ctrl + C''' keys to '''terminate''' this '''loop'''.

|-
|| Switch to Editor
|| Switch back to the '''editor.'''

|-
|| <nowiki>[Editor] Modify: </nowiki>

loop {

println!(“Hello, World!”);

'''break;'''

}
|| In the '''editor''', modify the '''code''' as shown.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''break;'''
|| Here, we are using '''break statements''' to break the execution of the '''loop'''.

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch back to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| '''Run''' the project.

|-
|| <nowiki>[Terminal] Highlight:</nowiki>

'''Hello, World!'''
|| Notice now, we can see''' Hello, World''' printed only once.

This is because the '''loop''' breaks after one execution.

We can even have a '''condition check''' and break whenever the '''condition''' fails.

|-
|| Only Narration
|| This is the basic way to '''loop''' in '''Rust'''.

Next, let us learn about '''while loop'''.

|-
|| Switch to Editor
|| Switch back to the '''editor.'''

|-
|| <nowiki>[Editor] Type: </nowiki>

fn main(){

let mut a = 3;

while a!=0 {

println!(“{}”,a);

a = a - 1;

}

}
|| In the '''editor''', replace the '''code''' as shown.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''let mut a = 3;'''
|| Here we have initialized a '''mutable variable a''' and assigned the value '''3 '''to it.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''while a!=0 {'''
|| After this, the '''while keyword''' is used to initialize a '''while loop.'''

'''While keyword''' is followed by the '''condition a not equal to zero.'''

Until and unless the '''condition''' returns '''false,''' the '''block''' gets executed.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''println!(“{}”,a);'''

'''a = a - 1;'''
|| Here we are printing the number and then reducing the value by''' 1.'''

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch back to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| '''Run''' the project and see the output.

|-
|| <nowiki>[Terminal] Highlight:</nowiki>

3

2

1
|| So now, we have successfully executed the '''while loop'''.

Only when the value of '''a''' is '''zero''' the '''condition''' returns '''false''' and the '''block''' will stop getting executed.

So '''0''' is not printed.

|-
|| Only Narration
|| Now let us learn about '''for loop.'''

|-
|| Switch to Editor
|| Switch back to the '''editor.'''

|-
|| <nowiki>[Editor] Type: </nowiki>

'''fn main(){'''

'''<nowiki>let arr = [2,3,5,7,11];</nowiki>'''

'''for value in arr.iter() {'''

'''println!(“Value = {}”,value);'''

'''}'''

'''}'''
|| In the '''editor''', replace the '''code''' as shown.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''<nowiki>let arr = [2,3,5,7,11];</nowiki>'''
|| Here we have initialized an '''array''' with few '''number elements''' in it.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''for value in arr.iter() {'''
|| So here '''value '''means each and every '''number element''' present in the '''array.'''

In the first iteration, the value will be '''2.'''

And in the second iteration, the value will be '''3''' and so on.

|-
|| <nowiki>[Video Editing]:</nowiki>

Notify:

https://doc.rust-lang.org/std/iter/index.html
|| '''Rust std''' module, provides three forms of iteration.

Here, we are using''' iter() method''' which iterates over &T.

For more details, on '''iter method''' refer to the link.

In our example, The '''iter() method''' will iterate over all the values in the '''array'''.

|-
|| <nowiki>[Editor] Highlight:</nowiki>

'''println!(“Value = {}”,value);'''
|| And, in the '''block''' we are printing the value for each and every iteration.

|-
|| Ctrl + S
|| Save the file.

|-
|| Switch to terminal
|| Switch back to the '''terminal.'''

|-
|| <nowiki>[Terminal] Type: </nowiki>

'''cargo run '''<nowiki>[Enter]</nowiki>
|| '''Run''' the project.

|-
|| <nowiki>[Terminal] Highlight:</nowiki>

'''Value = 2'''

'''Value = 3'''

'''Value = 5'''

'''Value = 7'''

'''Value = 11'''
|| The '''loop''' has executed successfully and printed all the values in the '''array.'''

We can see the '''for loop''' has been executed once for each and every '''element''' in the '''array'''.

And on reaching the end of the '''array''', the '''for loop''' stopped executing.

|-
|| Only narration
|| That’s how a '''for loop''' works in '''Rust'''.

|-
|| Only narration
|| With this we have come to the end of this tutorial.

Let’s summarize.

|-
|| Slide''': '''Summary''' '''
|| In this tutorial, we have learnt:

* '''if/else control flow statements'''
* Different '''types''' of '''loops''' and
* Their '''syntax''' and usage

|-
|| Slide: Assignment
|| As an assignment,

* Go to the project folder '''rust-assignment'''
* In the '''main.rs''' file
** Create a '''array '''named '''n '''and assign '''10 '''random numbers to it
** '''Loop '''over the '''array '''and
** Count the number''' '''of '''even '''values and '''odd '''values
** Print the count of '''odd '''and '''even '''values
* '''Compile '''and '''execute '''the project.
* Observe the output in the '''Terminal'''

|-
|| '''Slide: '''About Spoken Tutorial Project
||
* The video at the following link summarises the Spoken Tutorial project.
* Please download and watch it

|-
|| '''Slide:''' Spoken tutorial workshops
||
* We conduct workshops using spoken tutorials and give certificates.
* For more details, please write to us.

|-
|| Slide: Forum questions
|| Pls post your timed queries in this forum

|-
|| Slide: Acknowledgement
|| Spoken Tutorial Project is funded by Ministry of Education, Government of India

|-
|| Slide: Thanks
|| This is Jayesh signing off. Thank you for joining

|}

← Older revision		Revision as of 05:37, 2 February 2021
Line 319:		Line 319:


−	This is the '''if-~~elseif~~-else statement'''.	+	This is the '''if - else if - else statement'''.

	\|-		\|-

@@ Line 24: / Line 24: @@
 || In this tutorial, we will learn about the:
 * '''if/else control flow statements'''
-* Different '''types''' of '''loops'''
+* Different '''types''' of '''loops''' supported in '''Rust'''
-* '''Syntax''' of all the '''control flow statements '''and their usage
+* '''Syntax''' of all the '''control flow statements''' and their usage
 |-
@@ Line 34: / Line 34: @@
 * '''Visual Studio Code''' version 1.45.0 ('''code editor''')
-However you may use any other '''editor''' of your choice.
+However, you may use any other '''editor''' of your choice.
 |-
@@ Line 116: / Line 116: @@
 <nowiki>[Enter]</nowiki>
-|| Let us create a new '''project''' named '''controlFlow.'''
+|| Let us create a new '''project''' named '''control_flow.'''
@@ Line 126: / Line 126: @@
-I will use '''Visual Studio Code editor '''for this demonstration.
+I will use '''Visual Studio Code editor''' for this demonstration.
 |-
@@ Line 143: / Line 143: @@
-Then click on the '''OK '''button at the top right corner.
+Then click on the '''OK''' button at the top right corner.
 |-
@@ Line 149: / Line 149: @@
 Click on '''control_flow'''
-|| Under the '''EXPLORER''' section, expand the '''project''' folder “'''controlFlow'''” by clicking on it.
+|| Under the '''EXPLORER''' section, expand the '''project''' folder “'''control_flow'''” by clicking on it.
 |-
@@ Line 216: / Line 216: @@
 cd '''control_flow'''<nowiki>[Enter]</nowiki>
-|| Go to the '''project''' folder '''controlFlow '''using the '''cd command.'''
+|| Go to the '''project''' folder '''control_flow '''using the '''cd command.'''
 |-
@@ Line 293: / Line 293: @@
 Here, we emphasise that only an '''if condition''' can exist without an '''else statement.'''
 |-
@@ Line 392: / Line 388: @@
 |-
 || Only narration
-|| That’s how the '''if-else if-else statements''' work in '''Rust'''.
+|| That’s how the '''if - else if - else statements''' work in '''Rust'''.
 |-

@@ Line 3: / Line 3: @@
 Author: Jayesh Katta Ramalingaiah
-Domain Reviewer:
+Domain Reviewer: Vigneshwer Dhinakaran
-Novice Reviewer:
+Novice Reviewer: Praveen S.
 Keywords: Rust, variables, if, else, else if, conditions