Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on
2025-05-06T09:01:05Z

Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || <span style="color:#000000;">Welcome to the Spoken Tutorial on </span><span style="color:#000000..."

New page
{| border="1"
|-
|| '''Visual Cue'''
|| '''Narration'''
|-
|| '''Slide 1'''
|| <span style="color:#000000;">Welcome to the Spoken Tutorial on </span><span style="color:#000000;">'''Functions and Control Flow '''</span><span style="color:#000000;">in </span><span style="color:#000000;">'''Rust.'''</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 2'''</div>

<div style="color:#000000;">'''Learning Objectives'''</div>
|| In this tutorial, we will learn about
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Control Flow Statement and</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Functions</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.153cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide </span>3'''

<div style="color:#000000;">'''System Requirements'''</div>
|| <span style="color:#000000;">This tutorial</span> is recorded<span style="color:#000000;"> using</span>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Ubuntu Linux OS version 22.04</div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">Rust 1.</span><span style="color:#000000;">80</span><span style="color:#000000;">.0 </span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">Visual </span>S<span style="color:#000000;">tudio </span>C<span style="color:#000000;">ode 1.19.0</span></div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.153cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide </span>4'''

<div style="color:#000000;">'''Prerequisites'''</div>
||
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">You should be familiar with compiling and running Rust files</div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">If not go through the </span><span style="color:#000000;">prerequisite</span><span style="color:#000000;"> Rust tutorial on this website</span></div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.153cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide'''</span> '''5'''

<div style="color:#000000;">'''Code Files'''</div>
||
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">The files used in this tutorial are provided in the </span><span style="color:#000000;">'''Code files'''</span><span style="color:#000000;"> link of this tutorial page</span></div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Please download and extract the files.</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Make a copy and then use them while practicing.</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.153cm;padding-right:0.191cm;"
| style="color:#000000;" |
| style="color:#000000;" | First we will see about conditional statements in Rust.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.153cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide</span> 6'''

<div style="color:#000000;">'''Conditional Statements'''</div>
|| <div style="color:#000000;">Rust supports </div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">if </div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">else if </div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">else</span><span style="color:#000000;">''' '''</span></div>

statements <span style="color:#000000;">for making decisions based on conditions.</span>

It <span style="color:#000000;">always returns a boolean value.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">Open </span><span style="color:#000000;">'''Visual'''</span><span style="color:#000000;"> </span><span style="color:#000000;">'''code editor'''</span>
|| <span style="color:#000000;">Let us open the </span><span style="color:#000000;">'''visual code editor'''</span><span style="color:#000000;"> and</span><span style="color:#000000;"> understand the control </span><span style="color:#000000;">statements</span><span style="color:#000000;"> with examples.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">In the menu bar, click on </span><span style="color:#000000;">'''terminal'''</span><span style="color:#000000;"> and select</span><span style="color:#000000;">''' New Terminal'''</span>

<div style="color:#000000;">We can see a terminal window at the bottom.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| > cd '''MyRustProject'''

'''>''' '''cargo new functions'''

|| Go to our working directory '''MyRustProject''' as explained earlier.

Type the command '''cargo new functions '''and press '''Enter'''

Open the created project as shown.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;"></div>

<div style="color:#000000;"></div>
|| <span style="background-color:#ffffff;color:#000000;">In the </span><span style="background-color:#ffffff;color:#000000;">'''main.rs '''</span><span style="background-color:#ffffff;color:#000000;">file, </span><span style="background-color:#ffffff;">copy and paste the code from the code file.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">fn main() { </div>
<div style="color:#000000;">let n = 100; </div>
<div style="color:#000000;">if n>100{ </div>
<div style="color:#000000;">println!("Greater than 100"); </div>
<div style="color:#000000;">}else if n==100{ </div>
<div style="color:#000000;">println!("Equal to 100"); </div>
<div style="color:#000000;">}else { </div>
<div style="color:#000000;">println!("Smaller than 100"); </div>
<div style="color:#000000;">} </div>

<div style="color:#000000;">} </div>
|| <span style="color:#000000;">Let us look at this example </span>for an''' if else'''<span style="color:#000000;"> statement.</span>

<span style="color:#000000;">If n is greater than 100, it </span>prints a<span style="color:#000000;"> </span>“greater than 100”<span style="color:#000000;"> statement. </span>

<div style="color:#000000;">If n equals 100, the second print statement will be executed. </div>

<span style="color:#000000;">If n is less than 100, it prints </span>“smaller than 100”<span style="color:#000000;">.</span>

<span style="color:#000000;">You can include multiple </span><span style="color:#000000;">'''else if'''</span><span style="color:#000000;"> statements </span><span style="background-color:#ffffff;color:#000000;">to check multiple conditions in sequence. </span>

<div style="color:#000000;">The condition must be true to run the code wrapped to it.</div>

<span style="color:#000000;">Press </span><span style="color:#000000;">'''ctrl and s '''</span><span style="color:#000000;">to save the file.</span>

Now let us run the program.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| In the menu bar, click on '''Terminal''' and select '''New Terminal.'''

|| <span style="color:#000000;">In the menu bar, click on </span>'''T<span style="color:#000000;">erminal'''</span><span style="color:#000000;"> and select </span><span style="color:#000000;">'''New Terminal.'''</span>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| > cargo run
|| <span style="color:#000000;">In the terminal</span>,<span style="color:#000000;"> type </span><span style="color:#000000;">'''cargo run '''</span><span style="color:#000000;">to see the output.</span>

The output shows “equal to 100” as we have assigned '''n '''as 100 in the program.

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">Next let us see </span><span style="color:#000000;">'''loop'''</span><span style="color:#000000;"> statements in Rust</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">Slide</div>

<div style="color:#000000;">Loop</div>
||
* <div style="margin-left:1.27cm;margin-right:0cm;">A loop is used to repeat a block of code until the specified condition is met</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">The loop keyword creates an infinite loop unless you explicitly break out of it</div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">Rust provides several ways to loop, including </span><span style="color:#000000;">'''loop'''</span><span style="color:#000000;">, </span><span style="color:#000000;">'''while'''</span><span style="color:#000000;">, and </span><span style="color:#000000;">'''for'''</span></div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| Let us see an example for a '''loop''' program.

Clear the code window and r<span style="color:#000000;">eplace the code from the code file as shown</span>.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">fn main() {</div>
<div style="color:#000000;">let mut count = 0;</div>
<div style="color:#000000;">loop {</div>
<div style="color:#000000;">count += 1;</div>
<div style="color:#000000;">println!("Count: {}", count);</div>
<div style="color:#000000;">if count == 5 {</div>
<div style="color:#000000;">break;</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">}</div>
|| <span style="color:#000000;">This example has a mutable variable named </span><span style="color:#000000;">'''count'''</span><span style="color:#000000;"> which is assigned to the value 0.</span>
<span style="color:#000000;">A loop is created in which it increases the </span><span style="color:#000000;">'''count'''</span><span style="color:#000000;"> variable by 1</span>.

It<span style="color:#000000;"> prints the value of count in the current iteration. </span>

<span style="color:#000000;">It will also check for the </span><span style="color:#000000;">'''if '''</span><span style="color:#000000;">statement condition. </span>

<div style="color:#000000;">When the variable count will be equal to 5, it will stop executing and come out of the loop. </div>

<span style="color:#000000;">If there is no if statement, it will execute infinitely.Press </span><span style="color:#000000;">'''ctrl and s '''</span><span style="color:#000000;">to save the file.</span>

Let us run the program

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

We can see the count variable is printed from 1 to 5.

It stops executing when the count reaches 5.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">Next we will </span>see how<span style="color:#000000;"> the </span><span style="color:#000000;">'''while'''</span><span style="color:#000000;"> loop works.</span>

Replace<span style="color:#000000;"> the code from the codefile with the </span><span style="color:#000000;">'''while'''</span><span style="color:#000000;"> loop program.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">fn main() {</div>

<div style="color:#000000;">let mut counter = 1;</div>
<div style="color:#000000;">// usage of while loop</div>
<div style="color:#000000;">while counter < 6 {</div>
<div style="color:#000000;">println!("{}", counter);</div>
<div style="color:#000000;">counter += 1;</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">}</div>
|| <span style="color:#000000;">The </span><span style="color:#000000;">'''while'''</span><span style="color:#000000;"> loop runs as long as a condition is true.</span>

<span style="color:#000000;">Here, the loop keeps running till the </span><span style="color:#000000;">'''counter'''</span><span style="color:#000000;"> variable is less than 6. </span>

<div style="color:#000000;">Inside the loop, we are increasing the value of the counter by 1.</div>

After the 5th<span style="color:#000000;"> iteration, the value </span>of the counter<span style="color:#000000;"> will be 6.</span>

<div style="color:#000000;">So the condition, counter < 6 becomes false and the loop is terminated.</div>

<div style="color:#000000;">Save the program.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

<div style="color:#000000;">Check the output.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="background-color:#ffffff;color:#000000;">Next we will see </span><span style="background-color:#ffffff;">about </span><span style="background-color:#ffffff;">'''For'''</span><span style="background-color:#ffffff;color:#000000;"> loop.</span>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide</span> 7'''

<div style="color:#000000;">'''For loop'''</div>
||
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">The </span><span style="color:#000000;">'''for'''</span><span style="color:#000000;"> </span><span style="color:#000000;">loop iterates over a range or a collection</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">An </span><span style="color:#000000;">'''iterator '''</span><span style="color:#000000;">which provides a way to access elements one at a time.</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">In a </span><span style="color:#000000;">'''For'''</span><span style="color:#000000;"> loop, many collections like arrays, vectors, and ranges, implement the </span><span style="color:#000000;">'''Iterator'''</span><span style="color:#000000;"> </span></div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide</span> 8'''

<div style="color:#000000;">'''For loop -example'''</div>

<span style="color:#000000;">'''fn'''</span><span style="color:#000000;"> main() {</span>
<span style="color:#000000;">'''for'''</span><span style="color:#000000;"> n </span><span style="color:#000000;">'''in'''</span><span style="color:#000000;"> 0..11 {</span>
<div style="color:#000000;">println!("{}", n);</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">}</div>

|| The''' For'''<span style="color:#000000;"> loop has a definite </span>start<span style="color:#000000;"> and endpoint with increment for each iteration.</span>

<div style="color:#000000;">A range with two dots like 0..11 is inclusive on the left.</div>

<div style="color:#000000;">i.e it starts at 0 and exclusive on the right. i.e ends at 10</div>

<span style="color:#000000;">This program will</span><span style="color:#000000;"> </span><span style="color:#000000;">print numbers from 0 to 10</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Next let us see an example of a for loop with an iterator method.

Clear the code window and copy and paste the code from the code file.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">fn main() {</div>

<div style="color:#000000;">let data = [2, 1, 17, 99, 34, 56];</div>
<div style="color:#000000;">// iterator</div>
<div style="color:#000000;">//let numbers_iterator = data.iter();</div>
<div style="color:#000000;">for i in data.iter(){</div>
<div style="color:#000000;">println!("{}", i);</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">}</div>
|| <div style="color:#000000;"></div>

<span style="color:#000000;">In this code, we have an array </span><span style="color:#000000;">'''‘data’'''</span><span style="color:#000000;"> containing five integers. </span>

<span style="color:#000000;">The </span><span style="color:#000000;">'''data.iter() '''</span><span style="color:#000000;">method creates an iterator for the array </span><span style="color:#000000;">'''data'''</span><span style="color:#000000;">.</span>

<span style="color:#000000;">The </span><span style="color:#000000;">'''for'''</span><span style="color:#000000;"> loop takes each element produced by the iterator and binds it to the variable </span><span style="color:#000000;">'''data'''</span><span style="color:#000000;">. </span>

<span style="color:#000000;">Inside the for loop, </span><span style="color:#000000;">'''println'''</span><span style="color:#000000;"> is used to print the value of each element.</span>

<div style="color:#000000;">Save the file.</div>

Let us execute the program.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

We can see the array elements are printed in sequence.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| We will learn some more concepts that work with a '''for''' loop.

Let us see how to use a reverse method in the for loop.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''fn'''</span><span style="color:#000000;"> main() {</span>

<div style="color:#252525;">for i in (1..=11).rev() {</div>
<div style="color:#252525;">println!("{i}...");</div>
<div style="color:#252525;">}</div>
<div style="color:#252525;">println!("Launch!");</div>
<div style="color:#000000;">}</div>
|| Copy and paste the code from the code file.

If we want the range to include 11 as well, we can write it as '''(1..=11).'''
This is known as an inclusive range.

The '''rev() '''method is applied to the range to produce a reverse iterator.

This means the numbers will be fetched in reverse order.

<div style="color:#252525;">save the file.</div>

<div style="color:#252525;">Let us check the output</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

We can see the output displayed in the reverse order as expected.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| Next we will see how to print odd numbers using a for loop.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''fn'''</span><span style="color:#000000;"> main() {</span>
<div style="color:#000000;">for i in (1..11).rev() {</div>
<div style="color:#000000;">if i % 2 == 0 {</div>
<div style="color:#000000;">continue;</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">println!("{i}...");</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">println!("Launch!");</div>
<div style="color:#000000;">}</div>
|| <div style="color:#252525;">Copy and paste the code from the code file</div>

The''' if '''statement checks if''' i '''is divisible by 2.

If this condition is true, the '''continue''' statement is executed.

The '''continue''' statement skips the rest of the loop body for the current iteration and moves to the next one.

Save the program
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| In the terminal, check the output.

We can see the odd numbers are printed between 11 and 1.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">Next we will see about </span><span style="color:#000000;">'''Functions'''</span><span style="color:#000000;"> in Rust.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide</span> 9'''

<div style="color:#000000;">'''Functions'''</div>
||
* <div style="margin-left:1.27cm;margin-right:0cm;">It <span style="color:#000000;">is a set of statements to perform a specific task</span></div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Functions organize the program into logical blocks of code.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">Functions </span>make<span style="color:#000000;"> the code reusable.</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">It </span>structures<span style="color:#000000;"> your programs and </span>makes<span style="color:#000000;"> them more readable and maintainable.</span></div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 10'''</div>
<div style="color:#000000;">'''Function - Example'''</div>
<div style="color:#000000;">// define a function</div>
<div style="color:#000000;">fn greet() {</div>
<div style="color:#000000;">println!("Hello, World!");</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">fn main() {</div>
<div style="color:#000000;">//function call</div>
<div style="color:#000000;">greet();</div>
<div style="color:#000000;">}</div>
|| <div style="color:#000000;">Here, we have created a''' greet()''' function that prints "Hello, World!" .</div>

<div style="color:#000000;">To invoke the created function, we need to make a function call.</div>

<div style="color:#000000;">Notice that we are calling the function from inside '''main()'''.</div>

<div style="color:#000000;">In Rust, '''main() '''is also a function known as a built-in function that has a special meaning. </div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
| style="color:#000000;" | Next we will see how we can create a function with parameters.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <div style="color:#000000;">Let us understand the working of functions with examples.</div>

<span style="background-color:#ffffff;color:#000000;">In the </span><span style="background-color:#ffffff;color:#000000;">'''main.rs '''</span><span style="background-color:#ffffff;color:#000000;">file, replace the </span><span style="background-color:#ffffff;color:#000000;">'''code'''</span><span style="background-color:#ffffff;color:#000000;"> </span><span style="background-color:#ffffff;">from the code file.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">// define an add function that takes in two parameters</div>
<div style="color:#000000;">fn add(a: i32, b: i32) {</div>
<div style="color:#000000;">let sum = a + b;</div>
<div style="color:#000000;">println!("Sum of a and b = {}", sum);</div>
<div style="color:#000000;">}</div>
<div style="color:#000000;">fn main() {</div>
<div style="color:#000000;">// call add function with arguments</div>
<div style="color:#000000;">add(12, 10);</div>
<div style="color:#000000;">}</div>
|| In this example, the add function takes 2 parameters and gives the sum as output.

<div style="color:#000000;">Here, a and b are function parameters.</div>
<div style="color:#000000;">i32 is the data type of parameters.</div>
<span style="color:#000000;">12 and 10 are known as function arguments that are passed to the </span><span style="color:#000000;">'''add'''</span><span style="color:#000000;"> function.</span>

<div style="color:#000000;">That means 12 is assigned to a and 10 is assigned to b.</div>

<div style="color:#000000;">Save the file.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">In the terminal, type</span><span style="color:#000000;">''' cargo run '''</span><span style="color:#000000;">and see the output.</span>

It prints the sum of a and b as 22.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Next we will see an example for a function with return value.

Replace the code as shown.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||

fn area(length: i32, breadth: i32) -> i32 {

   length * breadth

}

fn main() {

    let k = area(5, 6);

    println!("Area of the rectangle = {k}");

}

Change the program to return lengthbreadth
||

In this example, we define a function to calculate the area of a rectangle.

The area function takes two parameters, length and breadth, both of type i32.

'''-> i32 -''' right arrow i32 before the opening curly bracket indicates the function's return type.

It returns an i32 value representing the area of the rectangle.

In the next line, notice the lack of a semicolon after length breadth.

In Rust, the absence of a semicolon signifies that this line is an expression.

The result value is returned by the function.
Save the file and run the program.

We can see the output as the area of the rectangle is 30.

Now let us add a semicolon at the end of length into Breadth statement .

Let us run the program and see how the program works.

It would not return a value and cause a compilation error.

<span style="background-color:#ffffff;">This time we get an error, </span><span style="background-color:#ffffff;">'''remove this semicolon to return this value.'''</span>

This is because it is being considered as a '''statement''' and not as a '''return''' value.

You can use either conventions 
* <div style="margin-left:1.247cm;margin-right:0cm;">lengthbreadth without semicolon or</div>
<div style="margin-left:1.247cm;margin-right:0cm;">return lengthbreadth with semicolon</div>
for returning the value.
Save the file and run the program

We can observe that the area of the rectangle is 30.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <div style="color:#000000;">This brings us to the end of this tutorial.</div>

<div style="color:#000000;">Let us summarize. </div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 11'''

'''Summary'''
|| In this tutorial, we learn about

<div style="margin-left:1.27cm;margin-right:0cm;">Control Flow Statement and</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Functions</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 12'''

'''Assignment'''
|| As an Assignment, do the following:
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="background-color:#ffffff;">In the </span><span style="background-color:#ffffff;">'''main.rs'''</span><span style="background-color:#ffffff;"> file</span></div>
<div style="margin-left:2.54cm;margin-right:0cm;">Create a '''function''' that accepts a '''number '''as a''' parameter'''</div>
<div style="margin-left:2.54cm;margin-right:0cm;">Print '''EVEN '''if the number is even</div>
** <div style="margin-left:2.54cm;margin-right:0cm;">Else print '''ODD'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">'''Compile '''and '''execute '''the project.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">Observe the output in the '''Terminal'''</div>

|-
| style="border:1pt solid #252525;padding-top:0.176cm;padding-bottom:0.176cm;padding-left:0.123cm;padding-right:0.176cm;" | '''Slide 13'''

<div style="color:#000000;">'''About Spoken Tutorial Project'''</div>
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;" | <span style="color:#000000;">This video </span>s<span style="color:#000000;">ummarizes the Spoken Tutorial project.</span>

<div style="color:#000000;">Please download and watch it.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 14'''

<div style="color:#000000;">'''Spoken Tutorial Workshops'''</div>
|| <span style="color:#000000;">The </span><span style="color:#000000;">'''Spoken Tutorial Project '''</span><span style="color:#000000;">Team conducts workshops and gives certificates.</span>

<div style="color:#000000;">For more details, please write to us.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 15'''</div>

<div style="color:#000000;">'''Forum for specific questions'''</div>
| style="color:#000000;" | Please post your timed queries in this forum
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 16'''

<div style="color:#000000;">'''Acknowledgement'''</div>
| style="color:#000000;" | Spoken Tutorial project was established at IIT Bombay by the Ministry of Education(MoE), Govt of India
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 17'''

<div style="color:#000000;">'''Acknowledgement'''</div>
|| <span style="color:#000000;">We would like to thank </span><span style="color:#000000;">'''Vishal Pokuri from VIT Vellore '''</span><span style="color:#000000;">for content contribution.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| '''Slide 18'''

<div style="color:#000000;">'''Thank You'''</div>
|| <span style="color:#000000;">This tutorial is contributed by </span><span style="color:#000000;">'''Nirmala Venkat'''</span><span style="color:#000000;"> and </span><span style="color:#000000;">'''Ketki Bhamble'''</span><span style="color:#000000;"> from the spoken tutorial team.</span>

<div style="color:#000000;">Thank you for joining.</div>

|-
|}
<div style="margin-left:-1.588cm;margin-right:-1.429cm;"></div>

Rust-Programming-Language/C2/Functions-and-Control-Flow/English - Revision history

Madhurig at 06:28, 27 May 2025

Madhurig at 05:59, 27 May 2025