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

Madhurig at 08:36, 11 October 2025

2025-10-11T08:36:27Z

Madhurig at 12:38, 7 October 2025

2025-10-07T12:38:23Z

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Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on
2025-10-06T09:01:54Z

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;">'''Collections 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="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">Collections an</span>d</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Types of Collections</div>

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 3'''</div>

<span style="color:#000000;">'''System Requirements'''</span>
||
* To record this tutorial I’m using the following setup.

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| <span style="color:#000000;">'''Slide'''</span><span style="color:#000000;"> </span><span style="color:#000000;">'''4'''</span>

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

|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide 6:'''</div>

<div style="color:#000000;">'''Collections'''</div>
|| Let us get started.
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">'''Collections'''</span><span style="color:#000000;"> are data structures that hold multiple values together</span></div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">They are used to store, retrieve, and manipulate groups of related values efficiently.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">Rust's collection types </span>are available<span style="color:#000000;"> in the </span><span style="color:#000000;">'''std::collections'''</span><span style="color:#000000;"> module </span></div>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.101cm;padding-right:0.191cm;"
|| <div style="color:#000000;">'''Slide7:'''</div>

<span style="color:#000000;">'''Types of Collections'''</span>
|| <div style="color:#000000;">Rust has 3 common collections that are used very often.</div>

* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">'''Vectors'''</span> <span style="background-color:#ffffff;color:#171717;">are dynamic arrays that can grow or shrink in size as needed.</span></div>

<div style="color:#000000;"></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">'''Hash Map'''</span> is a <span style="color:#000000;">key-value pair storage for fast lookups by key</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#000000;">'''HashSet'''</span> is a <span style="color:#000000;">collection of unique items with</span> no<span style="color:#000000;"> duplicates</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;">Open </span><span style="color:#000000;">'''Visual'''</span><span style="color:#000000;"> </span><span style="color:#000000;">'''code editor'''</span>
|| <span style="color:#000000;">Open the </span><span style="color:#000000;">'''Visual </span><span style="color:#000000;">S</span><span style="color:#000000;">tudio code 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 collections'''</span>

<div style="color:#000000;">'''In the menu bar, File >> Open folder >> Desktop >> MyRustProject >> collections'''</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 collections '''</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 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 mut fruits = vec!["Apple"];</div>

<div style="color:#000000;">fruits.push("Banana");</div>

<div style="color:#000000;">fruits.push("Cherry");</div>

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

<div style="color:#000000;">println!("{:?}", fruits.get(1)); // Some("Banana")</div>

<div style="color:#000000;">println!("{:?}", fruits.get(5)); // None</div>

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

<div style="color:#000000;">fruits.pop();</div>

<div style="color:#000000;">println!("{:?}", fruits); // ["Apple", "Banana"]</div>

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

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

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

<div style="color:#000000;">println!("Number of fruits: {}", fruits.len());</div>

<div style="color:#000000;">}</div>
|| <div style="color:#000000;">This code explains how the vector works.</div>

<span style="color:#252525;">We declare a </span><span style="color:#252525;">'''mutable vector'''</span><span style="color:#252525;"> called </span><span style="color:#252525;">'''fruits'''</span><span style="color:#252525;"> and i</span><span style="color:#252525;">t is initialized with </span><span style="color:#188038;">"Apple"</span><span style="color:#252525;">.</span>

<span style="color:#188038;">push()</span><span style="color:#252525;"> </span><span style="color:#252525;">is a </span><span style="color:#252525;">method to add elements</span><span style="color:#252525;"> </span><span style="color:#252525;">to the end of the vector.</span>

<span style="color:#252525;">We add </span><span style="color:#252525;">'''banana'''</span><span style="color:#252525;"> and </span><span style="color:#252525;">'''cherry'''</span><span style="color:#252525;"> to the second and third position using the </span><span style="color:#252525;">'''push'''</span><span style="color:#252525;"> method.</span>

W<span style="color:#252525;">e use the </span><span style="color:#252525;">'''get() '''</span><span style="color:#252525;">method which returns an </span><span style="color:#252525;">'''Option enum'''</span><span style="color:#252525;">.</span>

<span style="color:#252525;">'''fruits.get(1) '''</span><span style="color:#252525;">accesses the element at index 1 and prints </span><span style="color:#252525;">'''Some(“Banana”)'''</span>

<span style="color:#252525;">'''fruits.get(5) '''</span><span style="color:#252525;">is an invalid index and so it prints </span><span style="color:#252525;">'''None.'''</span>

<span style="color:#188038;">.pop()</span><span style="color:#252525;"> method</span><span style="color:#252525;"> removes the last element </span><span style="color:#252525;">from the vector.</span>

<span style="color:#252525;">In our case, </span><span style="color:#188038;">"Cherry"</span><span style="color:#000000;"> is </span><span style="color:#252525;">the last item and it gets removed.</span><span style="color:#188038;">.is_empty()</span><span style="color:#252525;"> </span><span style="color:#252525;">checks if the vector has </span><span style="color:#252525;">zero elements.</span><span style="color:#188038;">.len()</span><span style="color:#252525;"> returns the </span><span style="color:#252525;">number of elements </span><span style="color:#252525;">present in the vector.</span><span style="background-color:#ffffff;color:#000000;">Save the program.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
||
|| Run the code to see the output.

<span style="color:#188038;">is_empty()</span><span style="color:#252525;"> returns false since the </span><span style="color:#252525;">vector</span><span style="color:#252525;"> is not empty.</span>

<span style="color:#252525;">The vector has 2 elements and so the </span><span style="color:#252525;">'''len'''</span><span style="color:#252525;"> method prints,</span>

<span style="color:#188038;">Number of fruits as 2</span><span style="color:#252525;">.</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
| style="color:#252525;" |
|| <span style="color:#252525;">Next we will see about </span><span style="color:#252525;">'''HashMap.'''</span>
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
|| <div style="color:#252525;">use std::collections::HashMap;</div>

<div style="color:#252525;">fn main() {</div>

<div style="color:#252525;">let mut capitals = HashMap::new();</div>

<div style="color:#252525;">// Insert key-value pairs</div>

<div style="color:#252525;">capitals.insert("India", "New Delhi");</div>

<div style="color:#252525;">capitals.insert("USA", "Washington D.C.");</div>

<div style="color:#252525;">// Accessing elements</div>

<div style="color:#252525;">println!("{:?}", capitals.get("India"));  // Some("New Delhi")</div>

<div style="color:#252525;">println!("{:?}", capitals.get("France")); // None</div>

<div style="color:#252525;">// Removing an entry</div>

<div style="color:#252525;">capitals.remove("USA");</div>

<div style="color:#252525;">// Checking if key exists</div>

<div style="color:#252525;">if capitals.contains_key("India") {</div>

<div style="color:#252525;">println!("Found India's capital!");</div>

<div style="color:#252525;">}</div>
|| Copy paste the code from the Code file.

<span style="color:#252525;">In </span><span style="color:#252525;">Rust,</span><span style="color:#252525;"> </span><span style="color:#252525;">'''HashMap'''</span><span style="color:#252525;"> </span><span style="color:#252525;">is not available by default.</span><span style="color:#252525;">We need to </span><span style="color:#252525;">'''import '''</span><span style="color:#252525;">it</span><span style="color:#252525;"> </span><span style="color:#252525;">from the </span><span style="color:#188038;">std::collections</span><span style="color:#252525;"> </span><span style="color:#252525;">module to use it.</span>

<span style="color:#000000;">We create a </span><span style="color:#000000;">'''new, empty'''</span><span style="color:#000000;">,</span><span style="color:#000000;"> and </span><span style="color:#000000;">'''mutable'''</span><span style="color:#000000;"> </span><span style="color:#000000;">'''HashMap'''</span><span style="color:#000000;"> called </span><span style="color:#188038;">'''capitals'''</span><span style="color:#000000;">.</span>

<span style="color:#188038;">insert()</span><span style="color:#000000;"> method allows us to store a </span><span style="color:#000000;">'''key'''</span><span style="color:#000000;"> with its </span><span style="color:#000000;">value.</span>

The keys are the country names and the values are their capitals

<span style="color:#000000;">Similar to Vector, we </span>use the<span style="color:#000000;"> </span><span style="color:#000000;">'''.get()'''</span><span style="color:#000000;"> method, </span>to retrieve<span style="color:#000000;"> the value for</span> a<span style="color:#000000;"> given key.</span>

<span style="color:#000000;">If the key exists, it returns </span><span style="color:#188038;">Some(value)</span><span style="color:#000000;">.</span>

<span style="color:#000000;">If the key does not exist, it returns </span><span style="color:#188038;">None</span><span style="color:#000000;">.</span>

<span style="color:#000000;">The </span><span style="color:#188038;">remove()</span><span style="color:#000000;"> method </span><span style="color:#000000;">deletes </span><span style="color:#000000;">the entry with the given key.</span>

<span style="color:#252525;">It removes</span><span style="color:#000000;"> </span><span style="color:#188038;">"USA"</span><span style="color:#000000;"> and its capital </span><span style="color:#188038;">"Washington D.C."</span><span style="color:#000000;"> from the</span><span style="color:#000000;">''' HashMap.'''</span>

<span style="color:#000000;">The </span><span style="color:#188038;">contains_key()</span><span style="color:#000000;"> method checks if a </span><span style="color:#000000;">specific</span><span style="color:#000000;">''' key'''</span><span style="color:#000000;"> is present inside the</span><span style="color:#000000;">''' HashMap'''</span><span style="color:#000000;">.</span>

<span style="color:#252525;">The </span><span style="color:#188038;">len()</span><span style="color:#252525;"> method gives the</span><span style="color:#252525;"> total number of</span><span style="color:#252525;">''' key-value pairs'''</span><span style="color:#252525;"> present inside the </span><span style="color:#252525;">'''HashMap'''</span><span style="color:#252525;">.</span>

<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;" |
|| Run the program to see the output.
|- 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;">'''Hashset'''</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;"
|| <div style="color:#000000;">Slide:</div>

<div style="color:#000000;">Hashset:</div>
||
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#252525;">It</span><span style="color:#252525;"> is a</span><span style="color:#252525;"> collection of unique values.</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#252525;">It does not store duplicate entries, </span><span style="color:#252525;">that is</span><span style="color:#252525;"> </span><span style="color:#252525;">n</span><span style="color:#252525;">o two identical items can exist</span><span style="color:#252525;"> in it.</span></div>
* <div style="margin-left:1.27cm;margin-right:0cm;"><span style="color:#252525;">It is unordered — </span><span style="color:#252525;">T</span><span style="color:#252525;">he elements do not have a guaranteed order inside the set.</span></div>

|- 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:#252525;">Switch back to the visual code editor.</div>

Copy 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:#252525;">use std::collections::HashSet;</div>

<div style="color:#252525;">fn main() {</div>

<div style="color:#252525;">let mut names = HashSet::new();</div>

<div style="color:#252525;">// Inserting elements</div>

<div style="color:#252525;">names.insert("Jack");</div>

<div style="color:#252525;">names.insert("Joe");</div>

<div style="color:#252525;">names.insert("Jill");</div>

<div style="color:#252525;">names.insert("Joe"); // Duplicate, will be ignored</div>

<div style="color:#252525;">    if names.contains("Joe") {</div>

<div style="color:#252525;">        println!("Joe is present!");</div>

<div style="color:#252525;">    }</div>

<div style="color:#252525;">    // Removing an element</div>

<div style="color:#252525;">names.remove("Jill");</div>

<div style="color:#252525;">    // Checking length</div>

<div style="color:#252525;">    println!("Number of persons: {}", names.len());</div>
|| <span style="color:#252525;">In this code, we create a </span><span style="color:#252525;">'''mutable'''</span><span style="color:#252525;"> empty </span><span style="color:#188038;">HashSet</span><span style="color:#252525;">, called </span><span style="color:#188038;">'''names.'''</span>

<span style="color:#252525;">'''.insert()'''</span><span style="color:#252525;"> method insert elements to the </span><span style="color:#252525;">'''HashSet'''</span><span style="color:#252525;">.</span>

<span style="color:#252525;">When we try to insert the name</span><span style="color:#252525;"> </span><span style="color:#252525;">'''Joe'''</span><span style="color:#252525;"> </span><span style="color:#252525;">twice</span><span style="color:#252525;">,</span><span style="color:#252525;"> the </span><span style="color:#252525;">second insertion is </span><span style="color:#252525;">ignored</span><span style="color:#252525;"> </span><span style="color:#252525;">automatically</span><span style="color:#252525;">.</span>

<div style="color:#252525;"></div>

<span style="color:#252525;">Hash sets only store </span><span style="color:#252525;">unique </span><span style="color:#252525;">items.</span>

<span style="color:#000000;">The .</span><span style="color:#188038;">contains()</span><span style="color:#000000;"> method checks if a</span><span style="color:#000000;"> specific </span><span style="color:#000000;">'''item '''</span><span style="color:#000000;">is present inside the </span><span style="color:#000000;">'''HashSet'''</span><span style="color:#000000;">.</span>

<span style="color:#000000;">It will print a success message if the name </span><span style="color:#000000;">'''joe'''</span><span style="color:#000000;"> exists.</span>

<span style="color:#252525;">The </span><span style="color:#252525;">'''remove()'''</span><span style="color:#252525;"> method deletes a specific value from the set. </span>

<span style="color:#252525;">W</span><span style="color:#252525;">e can also loop through all the elements and print them.</span>

<span style="color:#252525;">The order is not guaranteed because </span><span style="color:#252525;">'''HashSets'''</span><span style="color:#252525;"> are unordered.</span>

<div style="color:#252525;">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><span style="color:#000000;">and see the output.</span>
|- 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;"
|| <div style="color:#000000;">'''Slide 8'''</div>

|| As an assignment,

<div style="color:#000000;">Write a Rust program that:</div>
# <div style="margin-left:1.247cm;margin-right:0cm;">Takes<span style="color:#000000;"> a list of numbers </span></div>
# <div style="margin-left:1.247cm;margin-right:0cm;"><span style="color:#000000;">Uses a HashSet to find all the </span><span style="color:#000000;">'''unique numbers'''</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;"
| style="color:#000000;" | '''Slide 9 Thank You'''
| style="color:#000000;" | Thanks for joining.
|-
|}
<div style="margin-left:-1.588cm;margin-right:-1.429cm;"></div>

@@ Line 22: / Line 22: @@
 |-
-|| '''Slide''' '''4'''
+|| '''Slide 4'''
 '''Code Files'''
@@ Line 30: / Line 30: @@
 |-
-|| '''Slide 6:'''
+|| '''Slide 5'''
 '''Collections'''
 || Let us get started.
 * '''Collections''' are data structures that hold multiple values together
 * They are used to store, retrieve, and manipulate groups of related values efficiently.
 * Rust's collection types are available in the '''std::collections''' module
 |-
-|| '''Slide7:'''
+|| '''Slide 6'''
 '''Types of Collections'''
@@ Line 55: / Line 56: @@
 || In the menu bar, click on '''Terminal''' and select''' New Terminal'''.
-|| In the menu bar, click on '''Terminal''' and select''' New Terminal'''.
+|| In the menu bar, click on '''Terminal''' and select ''' New Terminal'''.
 |-
@@ Line 67: / Line 68: @@
 || Let us go to our working directory '''MyRustProject''' as explained earlier.
-Type the command '''cargo new collections '''and press '''Enter.'''
+Type the command '''cargo new collections ''' and press '''Enter.'''
 Open the created project as shown.
 |-
 || Point to the '''main.rs''' file.
 || In the '''main.rs '''file, copy and paste the code from the Code file.
 |-
@@ Line 108: / Line 108: @@
 We declare a '''mutable vector''' called '''fruits''' and it is initialized with "Apple".
-push() is a method to add elements to the end of the vector.
+push() method is a method to add elements to the end of the vector.
 We add '''banana''' and '''cherry''' to the second and third position using the '''push''' method.
@@ Line 114: / Line 114: @@
 We use the '''get() '''method which returns an '''Option enum'''.
-'''fruits.get(1) '''accesses the element at index 1 and prints '''Some(“Banana”)'''
+'''fruits.get(1) ''' method accesses the element at index 1 and prints '''Some(“Banana”)''' method.
-'''fruits.get(5) '''is an invalid index and so it prints '''None.'''
+'''fruits.get(5) ''' method is an invalid index and so it prints '''None.'''
 .pop() method removes the last element from the vector.
-In our case, "Cherry" is the last item and it gets removed..is_empty() checks if the vector has zero elements..len() returns the number of elements present in the vector.Save the program.
+In our case, "Cherry" is the last item and it gets removed.
 |-
-||
+|| Type cargo run.
 || Run the code to see the output.
-is_empty() returns false since the vector is not empty.
+is_empty() method returns false since the vector is not empty.
 The vector has 2 elements and so the '''len''' method prints,
@@ Line 165: / Line 171: @@
 || Copy paste the code from the Code file.
-In Rust, '''HashMap''' is not available by default.We need to '''import '''it from the std::collections module to use it.
+In Rust, '''HashMap''' is not available by default.
-We create a '''new, empty''', and '''mutable''' '''HashMap''' called '''capitals'''.
+We need to '''import '''it from the std::collections module to use it.
 insert() method allows us to store a '''key''' with its value.
-The keys are the country names and the values are their capitals
+The keys are the country names and the values are their capitals.
 Similar to Vector, we use the '''.get()''' method, to retrieve the value for a given key.
@@ Line 189: / Line 197: @@
 Save the program.
 |-
-||
+|| type cargo run
 || Run the program to see the output.
 |-
@@ Line 195: / Line 203: @@
 || Next we will see about '''Hashset'''.
 |-
-|| Slide:
+|| '''Slide 7'''
-−
-Hashset:
+'''Hashset'''
 ||
 * It is a collection of unique values.
@@ Line 205: / Line 213: @@
 |-
 ||
-|| Switch back to the visual code editor.
+|| Switch back to the '''visual code editor'''.
 Copy paste the code from the Code file.
@@ Line 238: / Line 246: @@
 &nbsp;&nbsp;&nbsp;&nbsp;println!("Number of persons: {}", names.len());
-|| In this code, we create a '''mutable''' empty HashSet, called '''names.'''
 '''.insert()''' method insert elements to the '''HashSet'''.
@@ Line 245: / Line 254: @@
-Hash sets only store unique items.
+'''Hash''' sets only store unique items.
 The .contains() method checks if a specific '''item '''is present inside the '''HashSet'''.
@@ Line 259: / Line 268: @@
 Save the program.
 |-
-||
+||  In the terminal, type '''cargo run '''
-|| In the terminal, type '''cargo run '''and see the output.
+|| In the terminal, type '''cargo run ''' and see the output.
 |-
-||
+||'''Slide 8'''
 || This brings us to the end of this tutorial.
 Let us summarize.
 |-
-|| '''Slide 8'''
+|| '''Slide 9'''
 || As an assignment,
@@ Line 273: / Line 284: @@
 Write a Rust program that:
 # Takes a list of numbers
-# Uses a HashSet to find all the '''unique numbers'''.
+# Uses a HashSet to find all the  unique numbers.
 |-
-|| '''Slide 9 '''
+|| '''Slide 10 '''
 '''Thank You'''