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

Madhurig at 06:26, 1 October 2025

2025-10-01T06:26:01Z

Nirmala Venkat at 11:01, 22 September 2025

2025-09-22T11:01:47Z

Madhurig at 12:48, 19 September 2025

2025-09-19T12:48:54Z

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Nirmala Venkat: Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on
2025-09-19T09:17:04Z

Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''Slide 1''' || Welcome to the Spoken Tutorial on Welcome to the Spoken Tutorial on '''Strings '''in '''Rust.'''
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| Slide 2:

Learning Objective
|| In this tutorial, we will learn about
* <div style="margin-left:1.27cm;margin-right:0cm;">String data type</div>

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.171cm;padding-right:0.191cm;"
|| Slide 3:

System Requirement
||
* <div style="margin-left:1.27cm;margin-right:0cm;">To record this tutorial I’m using the following setup.</div>

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.171cm;padding-right:0.191cm;"
|| Slide 5:

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

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

'''Strings'''

|| The String data type in Rust can be classified as
* <div style="margin-left:1.27cm;margin-right:0cm;">String Literal(&str) i.e string slice and</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">String Object(String)</div>

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

'''String Literal'''

||
* <div style="margin-left:1.27cm;margin-right:0cm;">A string literal is a statically allocated string stored in the program's binary</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">It is written using '''double quotes (")'''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">String literals are also known as '''string slices.'''</div>

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| '''Slide 8:'''

'''String slice'''* <div style="margin-left:1.27cm;margin-right:0cm;">'''Eg: let name: &str = "Rust Program";'''</div>

||
* <div style="margin-left:1.27cm;margin-right:0cm;">A string slice is a reference to a part of a string. </div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">It's represented by the type''' &str '''</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">A string slice cannot be modified as it points to a part of memory that holds the string.</div>

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| Let us open the '''visual code editor.'''
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| click on '''terminal''' and select '''New Terminal'''

|| In the menu bar, click on '''Terminal''' and select '''New Terminal.'''

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

'''>''' '''cargo new stringsdemo'''

'''In the menu bar, File >> Open folder >> Desktop >> MyRustProject >> stringsdemo'''
|| Go to our working directory '''MyRustProject''' as explained earlier.

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

Open the created project as shown.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| In the '''main.rs '''file, copy and paste the '''code''' from the codefile.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| '''code example:'''

fn main() {

let s = String::from("Hello, world!");

let x = &s[0..5]; // A slice of the first 5 characters

println!("{}", x); // output: Hello

}
|| We have created a heap-allocated string''' s''' .

'''String::from '''creates a new String object from a string literal ("Hello, world!").

Variable '''x '''takes a slice of the string s.

0..5 is a '''range''' that means "from index 0 up to index 5".Note that the slicing excludes the end index character.

As '''x''' references part of '''s''', it doesn’t own the '''String'''. So no new memory is allocated to it. 

So, it gives you the substring "Hello".Save the program.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| <div style="color:#252525;"></div>

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

Point to the output.
|| Let us run the program and check the output.

In the menu bar, click on terminal and select '''New Terminal.'''

In the terminal, type '''cargo run'''

We can see''' Hello '''is printed as the output.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
| style="color:#252525;" |
|| Next we will see about '''String Objects.'''
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| Slide 9:

String Objects

||
* <div style="margin-left:1.27cm;margin-right:0cm;">String Object is mutable, growable and heap allocated string type.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">It is commonly used when the strings can be modified and dynamically sized.</div>
* <div style="margin-left:1.27cm;margin-right:0cm;">It automatically frees the memory when it goes out of scope.</div>

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
| style="color:#000000;" |
|| Next we will see some of the common methods used with string objects.

Copy and paste the code from the code file for each function in the below demonstration.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| fn main() {

let s = String::from("Hello World");

println!("Length: {}", s.len()); // Outputs: 11

}

> cargo run
|| First we will see how to use the '''len()''' function.

The '''len()''' function returns the total number of characters in a string, including the spaces.

Save the program.

Run the program. We can see the length of the string printed as 11.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| fn main() {

let mut s = String::from("Hello");

s.clear();

println!("Cleared string: {}", s); // Outputs an empty line

}
|| Next we will see about the '''clear()''' function.

The''' clear()''' function clears the string and returns an empty string.

Run the program.

We can see the empty string as output.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| fn main(){

let s = String::from("I love Rust");

let new_s = s.replace("love", "enjoy");

println!("{}", new_s); }

// Outputs: I enjoy Rust
|| Next we will check how the '''replace''' function works.

This program replaces all matches of a pattern with another string.

Let us run the program and verify the output.

We can see that the string “love” is replaced with “enjoy”.

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| fn main(){

let mut s = "Tutorial".to_string();

s.push('s');

println!("{}",s);

}
|| Let us see how the '''Push''' function works.

'''Push() '''function appends the given char to the end of this String.

Run the program .

In the output, “s” is added at the end of the string “tutorial”.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| fn main(){

let s = String::from("Hello, Rust, World");

for item in s.split(", ") {

println!("{}", item);

}

}
|| Next we will see about '''split''' function.

It splits the string, whenever it encounters a comma and space'''.'''

It returns an '''iterator''' over substrings separated by that pattern.

The '''for '''loop consumes the iterator and prints each substring on a new line.

In the terminal, run the program and check the output.

We can see each string slice printed on a new line.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| fn main() {

let str = String::from("Hello");

// Loop through each character in a string using chars() method

for char in str.chars() {

println!("{}", char);

}

}
|| This program shows how to use the '''chars()''' method.

We can use the '''chars() '''method of the string type to iterate over a string.

Let us check the output.

We can see each character of the string is printed in a separate line.
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| <div style="color:#000000;"></div>

fn main() {

let fullname = " Spoken Tutorials \r\n";

println!("Before trim ");

println!("length is {}",fullname.len());

println!();

println!("After trim ");

println!("length is {}",fullname.trim().len());

}
|| Next is about the '''trim''' function.

The '''trim()''' function removes leading and trailing spaces in a string. 

This will not remove the inline spaces.

Save the program.

Analyse the output.

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| Slide:

Additional reading material
||
* <div style="margin-left:1.27cm;margin-right:0cm;">Please go through the additional reading material provided in the link of this tutorial.</div>

* <div style="margin-left:1.27cm;margin-right:0cm;">You will learn more about string memory allocation concept and other string methods.</div>

|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| Slide:

Summary

In this tutorial, we learnt about
* <div style="margin-left:1.27cm;margin-right:0cm;">String data type</div>

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

Let us summarize. 
|- style="background-color:transparent;border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.191cm;padding-right:0.191cm;"
|| Slide:

Assignment

fn main(){

let mut title = " Spoken Tutorial".to_string();

title.push_str(" Project");

println!("{}",title);

}
|| As an assignment do the following:

* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Run the above code</div>
* <div style="color:#000000;margin-left:1.27cm;margin-right:0cm;">Understand the difference between '''push''' and '''push_str '''function.</div>

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

@@ Line 37: / Line 37: @@
 || The String data type in Rust can be classified as
-*String Literal(&str) i.e string slice and
+*String Literal(&str) that is string slice and
 *String Object(String)
@@ Line 58: / Line 58: @@
 ||
-*A string slice is a reference to a part of a string.
+* A string slice is a reference to a part of string.
 * It's represented by the type''' &str '''
-*A string slice cannot be modified as it points to a part of memory that holds the string.
+* A string slice cannot be modified as it points to a part of memory that holds the string.
 |-
-||
+|| Cursor on the panel.
 || Let us open the '''visual code editor.'''
 |-
-|| click on '''terminal''' and select '''New Terminal'''
+|| Click on '''terminal''' and select '''New Terminal'''
-−
 || In the menu bar, click on '''Terminal''' and select '''New Terminal.'''
@@ Line 84: / Line 83: @@
 |-
 ||
-|| In the '''main.rs '''file, copy and paste the '''code''' from the codefile.
+|| In the '''main.rs '''file, copy and paste the '''code''' from the Codefile.
 |-
 || '''code example:'''
@@ Line 101: / Line 100: @@
 '''String::from '''creates a new String object from a string literal ("Hello, world!").
-Variable '''x '''takes a slice of the string '''s'''.
+Variable '''x ''' takes a slice of the string '''s'''.
 to 5 is a '''range''' that means "from index 0 up to index 5".
@@ Line 107: / Line 106: @@
 Note that the slicing excludes the end index character.
-As '''x''' references part of '''s''', it doesn’t own the '''String'''. So no new memory is allocated to it.
+As '''x''' references part of '''s''', it doesn’t own the '''String'''.
 So, it gives you the substring "Hello".
@@ Line 118: / Line 119: @@
 In the terminal, type '''cargo run'''
-We can see ''' Hello '''is printed as the output.
+We can see ''' Hello ''' is printed as the output.
 |-
 ||
@@ Line 128: / Line 129: @@
 ||
-*String Object is mutable, growable and heap allocated string type.
+* String Object is mutable, growable and heap allocated string type.
-*It is commonly used when the strings can be modified and dynamically sized.
+* It is commonly used when the strings can be modified and dynamically sized.
 * It automatically frees the memory when it goes out of scope.
@@ Line 209: / Line 210: @@
 || Let us see how the '''Push''' function works.
-'''Push() '''function appends the given char to the end of this String.
+'''Push() ''' function appends the given char to the end of this String.
 Save the program.
@@ Line 266: / Line 267: @@
 |-
 ||
 fn main() {

@@ Line 115: / Line 115: @@
 || Point to the output.
 || Let us run the program and check the output.
 In the terminal, type '''cargo run'''
@@ Line 172: / Line 170: @@
 The ''' clear()''' function clears the string and returns an empty string.
 Run the program.
@@ Line 190: / Line 190: @@
 This program replaces all matches of a pattern with another string.
 Let us run the program and verify the output.
@@ Line 208: / Line 210: @@
 '''Push() '''function appends the given char to the end of this String.
 Run the program .
@@ Line 231: / Line 235: @@
 The '''for ''' loop consumes the iterator and prints each substring on a new line.
 In the terminal, run the program and check the output.
@@ Line 252: / Line 258: @@
 We can use the '''chars() '''method of the string type to iterate over a string.
 Let us check the output.