Rust-Programming-Language/C2/Functions/English - Revision history

Madhurig at 12:08, 14 August 2025

2025-08-14T12:08:56Z

Madhurig at 11:55, 14 August 2025

2025-08-14T11:55:18Z

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Nirmala Venkat at 06:43, 12 August 2025

2025-08-12T06:43:51Z

Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on
2025-08-12T06:43:19Z

Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || <span style="color:#000000;">Welcome to the Spoken Tutorial on </span><span style="color:#00000..."

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 '''</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;">Functions</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.136cm;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;">Ubuntu Linux OS version 22.04</div>
* <span style="color:#000000;">Rust 1.</span><span style="color:#000000;">80</span><span style="color:#000000;">.0 </span>
* <span style="color:#000000;">Visual </span>S<span style="color:#000000;">tudio </span>C<span style="color:#000000;">ode 1.19.0</span>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.136cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide </span>4'''

<div style="color:#000000;">'''Prerequisites'''</div>
||
* <span style="color:#000000;">You should be familiar with compiling and running </span><span style="color:#000000;">a </span><span style="color:#000000;">Rust </span>program

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.136cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide'''</span> '''5'''

<div style="color:#000000;">'''Code File'''</div>
||
* <span style="color:#000000;">The following code files </span>is<span style="color:#000000;"> required to practise this tutorial</span>
* <span style="color:#000000;">Th</span>is<span style="color:#000000;"> files </span>is<span style="color:#000000;"> provided in the code files link of this tutorial page</span>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.136cm;padding-right:0.191cm;"
|| '''Slide 6'''

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

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.136cm;padding-right:0.191cm;"
|| '''Slide 7'''

'''Function - Example'''
// define a function
fn greet() {

println!("Hello, World!");

}
fn main() {

//function call
greet();

}
||
* <span style="color:#000000;">Here, we have created a</span><span style="color:#000000;">''' greet()'''</span><span style="color:#000000;"> function that prints "Hello, World!" .</span>
* <div style="color:#000000;">To invoke the created function, we need to make a function call.</div>
* <span style="color:#000000;">Notice that we are calling the function from inside </span><span style="color:#000000;">'''main()'''</span><span style="color:#000000;">.</span>
* <span style="color:#000000;">In Rust, </span><span style="color:#000000;">'''main() '''</span><span style="color:#000000;">is also a function known as a built-in function that has a special meaning. </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;">.'''</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;">// 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.

Here, a and b are function parameters.

i32 is the data type of parameters.

12 and 10 are known as function arguments that are passed to the '''add''' function.

That means 12 is assigned to a and 10 is assigned to b.

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

|- 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 .

Save the file.
|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;" |
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;" | Let us run the program and see how the program works.
|-
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;" |
| style="border-top:none;border-bottom:1pt solid #000000;border-left:1pt solid #000000;border-right:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;" |

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:2.018cm;margin-right:0cm;">lengthbreadth without semicolon or</div>
<div style="margin-left:2.018cm;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;"
|| '''Slide 11'''

<div style="color:#000000;">'''Summary'''</div>

In this tutorial, we learn about
<div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">'''Functions'''</div>

|| This brings us to the end of this tutorial.

Let us summarize.
|- 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:

* <span style="background-color:#ffffff;">In the </span><span style="background-color:#ffffff;">'''main.rs'''</span><span style="background-color:#ffffff;"> file</span>
Create a '''function''' that accepts a '''number '''as a''' parameter'''
* Print '''EVEN '''if the number is even
* Else print '''ODD'''
* '''Compile '''and '''execute '''the project.
* Observe the output in the '''Terminal'''

|- 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>
|| Thank you for joining.

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

@@ Line 36: / Line 36: @@
 ||
 * The following code files is required to practise this tutorial
-* This files is provided in the code files link of this tutorial page
+* This file is provided in the code files link of this tutorial page
 |-
@@ Line 42: / Line 42: @@
 '''Functions'''
-||
+|| We will see about functions in Rust.
 * It is a set of statements to perform a specific task
 * Functions organize the program into logical blocks of code.
 * Functions make the code reusable.
 * It structures your programs and makes them more readable and maintainable.
 |-
-|| '''Slide 7'''
+|| '''Slide 8'''
 '''Function - Example'''
@@ Line 73: / Line 78: @@
 |-
 || Open '''Visual''' '''code editor'''
-|| Let us open the '''visual code editor.'''
+|| Let us open the '''Visual code editor.'''
 |-
 ||
@@ Line 84: / Line 89: @@
 '''>''' '''cargo new functions'''
-|| Go to our working directory '''MyRustProject''' as explained earlier.
+|| Let us go to our working directory '''MyRustProject''' as explained earlier.
 Type the command '''cargo new functions '''and press '''Enter'''
@@ Line 91: / Line 96: @@
 |-
 ||
-|| In the '''main.rs '''file, copy and paste the code from the code file.
+|| In the '''main.rs '''file, copy and paste the code from the Code file.
 |-
 || // define an add function that takes in two parameters
@@ Line 115: / Line 120: @@
 Save the file.
 |-
-||
+|| Click on '''Terminal''' and select '''New Terminal.'''
 || In the menu bar, click on '''Terminal''' and select '''New Terminal.'''
 |-
-|| Type''' cargo run '''
+|| Type ''' cargo run '''
 || In the terminal, type''' cargo run '''and see the output.
@@ Line 139: / Line 144: @@
 Change the program to return length*breadth
-In this example, we define a function to calculate the area of a rectangle.
+||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.
+'''-> 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.
@@ Line 159: / Line 163: @@
 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 .
+Now let us add a semicolon at the end of length into Breadth statement.
 Save the file.
@@ Line 166: / Line 170: @@
 || Let us run the program and see how the program works.
 |-
-||
+|| Show the error.
 || It would not return a value and cause a compilation error.

@@ Line 205: / Line 205: @@
 * <span style="background-color:#ffffff;">In the </span><span style="background-color:#ffffff;">'''main.rs'''</span><span style="background-color:#ffffff;"> file</span>
- Create a '''function''' that accepts a '''number '''as a''' parameter'''
+*** Create a '''function''' that accepts a '''number '''as a''' parameter'''
 *** Print '''EVEN '''if the number is even
 *** Else print '''ODD'''