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

Madhurig at 05:41, 12 September 2025

2025-09-12T05:41:32Z

Madhurig at 05:19, 12 September 2025

2025-09-12T05:19:47Z

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Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on
2025-09-03T09:40:21Z

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;">'''Arrays 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 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;">Arrays</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.118cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 3'''</div>

<div style="color:#000000;">'''System Requirements'''</div>
|| To record this tutorial I am using:
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Ubuntu Linux OS version 22.04</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Rust version 1.80.0 </div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Visual Studio Code version 1.19.0</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.118cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 4'''</div>

<div style="color:#000000;">'''Prerequisites'''</div>
| style="color:#000000;" | To follow this tutorial, you should be familiar with compiling and running Rust programs.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.118cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide'''</span><span style="color:#000000;"> </span><span style="color:#000000;">'''5'''</span>

<div style="color:#000000;">'''Code Files'''</div>
||
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">The following code file is required to practise this tutorial.</div>
'''arraysdemo.rs'''
<div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">This file is provided in the '''Code Files''' link of this tutorial page.</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.118cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 6'''</div>

<div style="color:#000000;">'''Arrays'''</div>
||
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">'''Arrays''' in '''Rust''' are collections of values of the same data type and have a fixed size</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Arrays once initialized cannot be resized</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">An array declaration allocates sequential memory blocks</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.118cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| <span style="color:#000000;">Let us understand how arrays </span>work<span style="color:#000000;"> in a</span><span style="color:#000000;">''' </span>R<span style="color:#000000;">ust'''</span><span style="color:#000000;"> program.</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>'''Visual Studio Code editor.'''

|| <span style="color:#000000;">Open the </span><span style="color:#000000;">'''Visual </span>S<span style="color:#000000;">tudio </span>C<span style="color:#000000;">ode editor.'''</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <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><span style="color:#000000;">.</span>
|| <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><span style="color:#000000;">.</span>

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

<span style="color:#000000;">'''>'''</span><span style="color:#000000;"> </span><span style="color:#000000;">'''cargo new </span>arraysdemo'''

<div style="color:#000000;">'''In the menu bar, File >> Open folder >> Desktop >> MyRustProject >> arraysdemo'''</div>
|| <span style="color:#000000;">Let us go to our working directory </span><span style="color:#000000;">'''MyRustProject'''</span><span style="color:#000000;"> as explained earlier.</span>

<span style="color:#000000;">Type the command </span><span style="color:#000000;">'''cargo new arraysdemo '''</span><span style="color:#000000;">and press </span><span style="color:#000000;">'''Enter.'''</span>

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

|| <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, copy and paste the code from the </span><span style="background-color:#ffffff;">C</span><span style="background-color:#ffffff;color:#000000;">ode 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 arr:[i32;4] = [10,20,30,40];</div>

<div style="color:#000000;">println!("First element: {}",arr[0]);</div>

<div style="color:#000000;">println!("Second element: {}", arr[1]);</div>

<div style="color:#000000;">println!("array size is :{}",arr.len());</div>

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

<div style="color:#000000;">Press Ctrl+s</div>
|| <div style="color:#000000;">We have declared an array with variable name as '''arr''' and its data type as '''i32''' and size as '''4.'''</div>

<span style="color:#000000;">The values </span>within<span style="color:#000000;"> the </span><span style="color:#000000;">'''square brackets'''</span><span style="color:#000000;"> are </span><span style="color:#000000;">'''array values'''</span><span style="color:#000000;">.</span>

In Rust, an array can store values of any '''datatype'''.

<span style="background-color:#ffffff;color:#000000;">To display the value of the </span><span style="background-color:#ffffff;color:#000000;">'''nth index'''</span><span style="background-color:#ffffff;color:#000000;"> in an </span><span style="background-color:#ffffff;color:#000000;">'''array, '''</span><span style="background-color:#ffffff;color:#000000;">we need to pass the </span><span style="background-color:#ffffff;color:#000000;">'''index.'''</span><span style="background-color:#ffffff;color:#000000;">Please note that the </span><span style="background-color:#ffffff;color:#000000;">'''array index'''</span><span style="background-color:#ffffff;color:#000000;"> starts from 0.</span>

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

<div style="color:#000000;">Let us execute the code and see the output.</div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <span style="color:#000000;">Click on terminal and select </span><span style="color:#000000;">'''New Terminal.'''</span>

<span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span><span style="color:#000000;">.</span>

<div style="color:#000000;">Point to the output.</div>
|| <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>

<span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span><span style="color:#000000;">.</span>

<span style="color:#000000;">It prints the first element as 10, second element as 20</span> and array size as 4.
|- 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>

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

<span style="color:#252525;">println!(</span><span style="color:#000000;">"array is {:?}"</span><span style="color:#252525;">, arr[5]);</span>

Press Ctrl+s
|| <div style="color:#000000;">Let us modify the code as shown.</div>

<div style="color:#000000;">We have 4 values in the array.</div>

<div style="color:#000000;">Let us try to access a value greater than 4, say 6th element where there is no value.</div>

<span style="color:#000000;">Add the </span><span style="color:#000000;">'''println'''</span><span style="color:#000000;"> statement as shown.</span>
<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;"
||

Point to the error
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

<span style="color:#000000;">We see an error- index out of bounds</span>.

<div style="color:#000000;">So, arrays in Rust are different as compared to other programming languages.</div>

<span style="color:#000000;">Th</span>is<span style="color:#000000;"> is because they have a fixed length.</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;">Next let us see an example of </span><span style="color:#000000;">'''mutable Array'''</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;"
|| <div style="color:#000000;">Delete the existing code.</div>

f<span style="color:#000000;">n main(){  </span>

<div style="color:#000000;">// an array with data type and size</div>

<div style="color:#000000;">    let mut colors: [&str; 3] = ["black", "blue", "red"];</div>

<div style="color:#000000;">    println!("Original colors: {:?}", colors);</div>

<div style="color:#000000;">// change the value of the 3rd element in the array</div>

<div style="color:#000000;">    colors[2] = "green";</div>

<div style="color:#000000;">    println!("changed colors = {:?}", colors);</div>

<div style="color:#000000;">  }</div>
|| <div style="color:#000000;">Clear the window and copy and paste the code from the Code file.</div>

<span style="color:#000000;">We have declared an array of </span><span style="color:#000000;">'''colors '''</span><span style="color:#000000;">with </span><span style="color:#000000;">'''mut'''</span>.

Here the data type and size of the array are specified<span style="color:#000000;">.</span>

<span style="color:#000000;"> </span>W<span style="color:#000000;">e have assigned a new value as “</span><span style="color:#000000;">'''green'''</span><span style="color:#000000;">” to the third element in the array.</span>

<span style="color:#000000;">As </span>the<span style="color:#000000;"> </span>created array<span style="color:#000000;"> </span>i<span style="color:#000000;">s mutable, it is possible to change the value.</span>

<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;"
|| Point to the output
|| <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>

The output shows the Original colors as black, blue, red.

And the changed <span style="color:#000000;">color values</span> as black, blue, green.
|- 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 some </span>p<span style="color:#000000;">owerful methods used to unlock the full potential of arrays.</span>

<div style="color:#000000;">Clear the window and copy and paste the code from the code files.</div>
|- 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 arr = [1, 2, 3, 4];</div>

<div style="color:#000000;">// Output: Is empty: false</div>

<div style="color:#000000;">println!("Is empty: {}", arr.is_empty()); </div>

<div style="color:#000000;">println!("2nd element: {}", arr.get(1).unwrap()); // 2</div>

<div style="color:#000000;">println!("First element: {}", arr.first().unwrap()); // 1</div>

<div style="color:#000000;">println!("Last element: {}", arr.last().unwrap()); // 4</div>

<div style="color:#000000;">let (left, right) = arr.split_at(2);</div>

<div style="color:#000000;">println!("Left slice:{:?}, Right slice:{:?}", left, right);</div>

<div style="color:#000000;">}</div>
|| <div style="color:#000000;"></div>

<div style="color:#000000;">Let us see the different methods used in arrays.</div>

<span style="color:#434343;">'''is_empty() '''</span><span style="color:#434343;">method </span>checks if the array has<span style="color:#434343;"> </span><span style="color:#434343;">any</span><span style="color:#434343;">''' elements'''</span><span style="color:#434343;">.</span>

<span style="color:#000000;">Here, </span><span style="color:#000000;">'''arr'''</span><span style="color:#000000;"> has 4 elements, so the result is </span><span style="color:#000000;">'''false'''</span><span style="color:#000000;">.</span>

We can access an element using the '''.get() '''method.

It takes the index value as the parameter. 

The '''get''' method returns an '''Option enum'''.

<span style="color:#434343;">.</span>'''get(1) '''returns an '''Option<i32> '''with the value at index 1 (which is 2).

<span style="color:#000000;">.unwrap() extracts the value (2) from </span><span style="color:#000000;">'''Some'''</span><span style="color:#000000;">.</span>

<span style="color:#188038;">Likewise,.</span><span style="background-color:transparent;color:#188038;">first()</span><span style="background-color:transparent;color:#434343;"> r</span><span style="color:#434343;">eturns </span><span style="color:#188038;">Some(1)</span><span style="color:#434343;"> </span><span style="color:#434343;">that is </span><span style="color:#434343;">the first element.</span>

<span style="color:#188038;">.unwrap()</span><span style="color:#434343;"> extracts </span><span style="color:#188038;">1</span><span style="color:#434343;"> from </span><span style="color:#188038;">Some(1)</span><span style="color:#434343;">.</span>

<span style="color:#188038;">.last()</span><span style="color:#434343;"> returns the last element as 4 </span>

<span style="color:#188038;">.split_at(2)</span><span style="color:#434343;"> splits the array at index </span><span style="color:#188038;">2</span><span style="color:#434343;">, producing two slices:</span>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#188038;">left</span><span style="color:#434343;"> contains the first two elements: </span><span style="color:#434343;">that is</span><span style="color:#188038;">[1, 2]</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#188038;">right</span><span style="color:#434343;"> contains the remaining elements: </span><span style="color:#434343;">that is</span><span style="color:#434343;"> </span><span style="color:#188038;">[3, 4]</span></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;"
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

<div style="color:#000000;"></div>
|| <span style="color:#000000;">In the terminal, type </span><span style="color:#000000;">'''cargo run'''</span>

<div style="color:#000000;">We can see the left slice and right slice output.</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 7'''</div>

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

<div style="color:#000000;">In this tutorial, we learn about</div>

<div style="color:#000000;">'''Arrays'''</div>
|| <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;"
|| <div style="color:#000000;">'''Slide 8'''</div>

<div style="color:#000000;">'''Assignment'''</div>
|| <div style="color:#000000;">As an Assignment, please do the following:</div>

* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Declare an array of 6 integers: [10, 20, 30, 40, 50, 60]</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Use a loop to print all elements in the array</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Create a slice of the array from index 2 to 4 </div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Print the slice using {:?}</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#000000;" | '''Slide 9 Thank You'''
| style="color:#000000;" | Thank you for joining.
|-
|}
<div style="margin-left:-1.588cm;margin-right:-1.429cm;"></div>

@@ Line 34: / Line 34: @@
 '''Code Files'''
 ||
 * The following code file is required to practise this tutorial.
-*'''arraysdemo.rs'''
 * This file is provided in the '''Code Files''' link of this tutorial page.
@@ Line 65: / Line 67: @@
 '''In the menu bar, File >> Open folder >> Desktop >> MyRustProject >> arraysdemo'''
 || Let us go to our working directory '''MyRustProject''' as explained earlier.
@@ Line 73: / Line 76: @@
 || Point to the '''main.rs''' file.
-|| 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'''.
 |-
 || fn main(){
@@ Line 88: / Line 91: @@
 Press Ctrl+s
-|| We have declared an array with variable name as '''arr''' and its data type as '''i32''' and size as '''4.'''
+|| We have declared an array with variable name as '''arr''' and its data type as '''i32''' and size as  4.
-The values within the '''square brackets''' are '''array values'''.
+The values within the  square brackets  are '''array values'''.
 In Rust, an array can store values of any '''datatype'''.
-To display the value of the '''nth index''' in an '''array, '''we need to pass the '''index.'''Please note that the '''array index''' starts from 0.
+To display the value of the '''nth index''' in an '''array, '''we need to pass the '''index.'''
 Save the program.
@@ Line 120: / Line 125: @@
 Let us try to access a value greater than 4, say 6th element where there is no value.
 Add the '''println''' statement as shown.
 Save the file.
 |-
 || Point to the error
-|| In the terminal, type '''cargo run'''
+|| In the terminal, type '''cargo run'''.
-We see an error- index out of bounds.
+We see an error- '''index out of bounds'''.
 So, arrays in Rust are different as compared to other programming languages.
@@ Line 153: / Line 159: @@
 &nbsp;&nbsp;}
-|| Clear the window and copy and paste the code from the Code file.
+|| Clear the window and copy and paste the code from the '''Code fil'''e.
 We have declared an array of '''colors '''with '''mut'''.
-Here the data type and size of the array are specified.
+Here the data type and size of  array are specified.
 &nbsp;We have assigned a new value as “'''green'''” to the third element in the array.
@@ Line 175: / Line 181: @@
 || Next let us see some powerful methods used to unlock the full potential of arrays.
-Clear the window and copy and paste the code from the code files.
+Clear the window and copy and paste the code from the '''code files'''.
 |-
 || fn main() {
@@ Line 198: / Line 204: @@
 ||  Let us see the different methods used in arrays.
-'''is_empty() '''method checks if the array has any''' elements'''.
+'''is_empty() ''' method checks if the array has any''' elements'''.
 Here, '''arr''' has 4 elements, so the result is '''false'''.
-We can access an element using the '''.get() '''method.
+We can access an element using the '''.get() ''' method.
 It takes the index value as the parameter.&nbsp;
@@ Line 208: / Line 214: @@
 The '''get''' method returns an '''Option enum'''.
-.'''get(1) '''returns an '''Option<i32> '''with the value at index 1 (which is 2).
+.'''get(1) '''returns an '''Option<i32> '''with the value at index 1,  which is 2.
 .unwrap() extracts the value (2) from '''Some'''.
-Likewise,.first() returns Some(1) that is the first element.
+Likewise,'''.first()''' returns '''Some(1)''' that is the first element.
-.unwrap() extracts 1 from Some(1).
+'''.unwrap()''' extracts 1 from '''Some(1)'''.
-.last() returns the last element as 4
+'''.last()''' returns the last element as 4
 .split_at(2) splits the array at index 2, producing two slices:
@@ Line 225: / Line 231: @@
 |-
 || In the terminal, type '''cargo run'''
 || In the terminal, type '''cargo run'''
@@ Line 245: / Line 250: @@
 '''Assignment'''
 || As an Assignment, please do the following:
-* Declare an array of 6 integers: [10, 20, 30, 40, 50, 60]
+* Declare an array of 6 integers
 * Use a loop to print all elements in the array
 * Create a slice of the array from index 2 to 4