LinkedIn skill assessment answers and questions — Rust (प्रोग्रामिंग भाषा)

“Rust is a modern and innovative programming language that has gained popularity for its focus on performance, सुरक्षा, and concurrency. इस व्यापक मार्गदर्शिका में, हम इसकी एक श्रृंखला प्रस्तुत करते हुए रोमांचित हैं skill assessment questions तथा जवाब के लिए विशेष रूप से तैयार किया गया Rust उपयोगकर्ताओं.

Whether you’re a seasoned developer looking to expand your capabilities or a beginner aiming to understand the basics of this powerful language, this resource is designed to help you become proficient in Rust और इसके अनुप्रयोग. Join us as we explore the core concepts of Rust programming, including ownership, borrowing, lifetimes, और अधिक, empowering you to harness the full potential of this cutting-edge language.”

Q1. Which type cast preserves the mathematical value in all cases?

• i64 as i32
• usize as u64
• i32 as i64
• f64 as f32

Q2. What do the vertical bars represent here?

str::thread::spawn(|| {
    println!("LinkedIn");
});

• a closure
• a thread
• a future
• a block

संदर्भ

Q3. Which choice is not a scalar data type?

• integer
• तैरना
• boolean
• टपल

Q4. _ cannot be destructured.

• Traits
• टुपल्स
• Enums
• Structs

संदर्भ

Q5. Which cargo command checks a program for error without creating a binary executable?

• cargo –संस्करण
• cargo init
• cargo build
• cargo check

Q6. शब्द डिब्बा and related phrases such as boxing a value are often used when relating to memory layout. What does डिब्बा refer to?

• It’s creating a pointer on the heap that points to a value on the stack.
• It’s creating a pointer on the stack that points to a value on the heap.
• It’s creating a memory guard around values to prevent illegal access.
• It’s an abstraction that refers to ownership. “Boxed” values are clearly labelled.

क्यू 7. What is an alternative way of writing slice that produces the same result?

...
let s = String::form("hello");
let slice = &s[0..2];

• let slice = &एस[len + 2];
• let slice = &एस[len – 2];
• let slice = &s.copy(0..2);
• let slice = &एस[..2];

क्यू 8. का उपयोग ? operator at the end of an expression is equivalent to _.

• a match pattern that branches into True or False
• calling ok_error()
• calling panic!()
• a match pattern that may result an early return

प्रश्न 9. Which is valid syntax for defining an array of i32 values?

• सरणी::with_capacity(10)
• [i32]
• सरणी::नया(10)
• [i32; 10]

प्र10. What syntax is required to take a mutable reference to T, when used within a function argument?

fn increment(i: T) {
    // body elided
}

• *mut T
• mut ref T
• mut &टी
• &mut T

प्रश्न 11. The smart pointers Rc and Arc provide reference counting. What is the API for incrementing a reference count?

• .जोड़ना()
• .incr()
• .clone()
• .increment()

संदर्भ

प्र12. What happens when an error occurs that is being handled by the question mark (?) operator?

• The error is reported and execution continues.
• An exception is raised. The effect(एस) of the exception are defined by the error! macro.
• The program panics immediately.
• Rust attempts to convert the error to the local function’s error type and return it as Result::Err. If that fails, the program panics.

प्रश्न 13. Which comment syntax is not legal?

• /*
• #
• //!
• //

प्र14. In matching patterns, values are ignored with _.

• .ignore()
• an underscore (_)
• ..
• छोड़ें

प्रश्न 15. Defining a _ requires a lifetime parameter.

• function that ends the lifetime of one of its arguments
• struct that contains a reference to a value
• function with a generic argument
• struct that contains a reference to a boxed value

Rust book reference

प्र16. Which example correctly uses std::संग्रह::HashMap’s Entry API to populate counts?

use std::collections::HashMap;
fn main() {
    let mut counts = HashMap::new();
    let text = "LinkedIn Learning";
    for c in text.chars() {
        // Complete this block
    }
    println!("{:?}", counts);
}

• ­

for c in text.chars() {
    if let Some(count) = &mut counts.get(&c) {
        counts.insert(c, *count + 1);
    } else {
        counts.insert(c, 1);
    };
}

• ­

for c in text.chars() {
    let count = counts.entry(c).or_insert(0);
    *count += 1;
}

• ­

for c in text.chars() {
    let count = counts.entry(c);
    *count += 1;
}

• ­

for c in text.chars() {
    counts.entry(c).or_insert(0).map(|x| x + 1);
}

संदर्भ

प्रश्न 17. Which fragment does not incur memory allocations while writing to a “फ़ाइल” (represented by a Vec)?

use std::collections::HashMap;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut v = Vec::<u8>::new();

    let a = "LinkedIn";
    let b = 123;
    let c = '🧀';

    // replace this line

    println!("{:?}", v);

    Ok(())
}

• :

write!(&mut v, "{}{}{}", a, b, c)?;

• :

v.write(a)?;
v.write(b)?;
v.write(c)?;

• :

v.write(a, b, c)?;

• :

v.write_all(a.as_bytes())?;
v.write_all(&b.to_string().as_bytes())?;
c.encode_utf8(&mut v);

1. Answered in rust user forum
2. संदर्भ

प्रश्न 18. Does the main function compile? यदि ऐसा है तो, क्यों? अगर नहीं, what do you need to change?

fn main() {
    let Some(x) = some_option_value;
}

• The code does not compile. let statements require a refutable pattern. जोड़ें if इससे पहले let.
• The code compiles. let statements sometimes require a refutable pattern.
• The code does not compile. let statements requires an irrefutable pattern. जोड़ें if इससे पहले let.
• The code compiles. let do not require a refutable pattern.

क्यू19. Which statement about lifetimes is false?

• Lifetimes were redundantly specified in previous version of Rust.
• Lifetimes are specified when a struct is holding a reference to a value.
• Lifetimes are specified when certain values must outlive others.
• Lifetimes are always inferred by the compiler.

प्र20. When used as a return type, which Rust type plays a similar role to Python’s None, JavaScript’s null, or the void type in C/C++?

• !
• None
• Null
• ()

प्र21. To convert a Result to an Option, which method should you use?

• .as_option()
• .ok()
• .to_option()
• .into()

प्र22. Which statement about the Clone तथा Copy traits is false?

• Copy is enabled for primitive, built-in types.
• Without Copy, Rust applies move semantics to a type’s access.
• When using Clone, copying data is explicit.
• Until a type implements either Copy या Clone, its internal data cannot be copied.

ref from stack overflow

प्र23. Why does this code नहीं compile?

fn returns_closure() -> dyn Fn(i32) -> i32 {
    |x| x + 1
}

• The returned fn pointer and value need to be represented by another trait.
• Closures are types, so they cannot be returned directly from a function.
• Closures are types and can be returned only if the concrete trait is implemented.
• Closures are represented by traits, so they cannot be a return type.

Rust book reference

प्र24. What smart pointer is used to allow multiple ownership of a value in various threads?

• Arc<T>
• Box<T>
• Both Arc<T> तथा Rc<T> are multithread safe.
• Rc<T>

Rust book reference

प्रश्न25. Which types are नहीं allowed within an enum variant’s body?

• zero-sized types
• structs
• trait objects
• floating-point numbers

संदर्भ

प्र26. Which statement about this code is true?

fn main() {
    let c = 'z';
    let heart_eyed_cat = '😻';
}

• Both are character literals.
• heart_eyed_cat is an invalid expression.
• c is a string literal and heart_eyed_cat is a character literal.
• Both are string literals.

संदर्भ

प्र27. Your application requires a single copy of some data type T to be held in memory that can be accessed by multiple threads. What is the thread-safe wrapper type?

• Mutex<Arc<T>>
• Rc<Mutex<T>>
• Arc<Mutex<T>>
• Mutex<Rc<T>>

Rust book reference

प्रश्न 28. Which idiom can be used to concatenate the strings a, b, c?

let a = "a".to_string();
let b = "b".to_string();
let c = "c".to_string();

• String::from(a,b,c)
• format!("{}{}{}", a, b, c)
• concat(a,b,c)
• a + b + c

प्र29. In this function. what level of access is provided to the variable a?

use std::fmt::Debug;

fn report<T:Debug>(a: &T) {
    eprintln!("info: {:?}", a);
}

• print
• read-only
• पढ़ना लिखना
• डिबग

क्यू30. Which choice is नहीं valid loop syntax?

• loop
• for
• while
• do

प्रश्न31. How do you construct a value of Status that is initialized to Waiting?

enum Status {
    Waiting,
    Busy,
    Error(String),
}

• let s = Enum::new(Status::Waiting);
• let s = new Status::Waiting;
• let s = Status::Waiting;
• let s = Status::new(Waiting);

प्र32. Which statement about enums is false?

• Enums are useful in matching patterns.
• Option is an enum type.
• Enum variants can have different types with associated data.
• अवधि enum is short for enummap

प्रश्न 33. What does an underscore (_) indicate when used as pattern?

• It matches everything.
• It matches underscores.
• It matches any value that has a length of 1.
• It matches nothing.

प्रश्न34. What is a safe operation on a std::cell:UnsafeCell<T>?

• ए &mut T reference is allowed. However it may not cpexists with any other references. and may be created only in single-threaded code.
• UnsafeCell<T> provides thread-safety. इसलिए, जो हंसना और दूसरों को हंसाना पसंद करता है &T references from multiple threads is safe.
• The only safe operation is the .get() तरीका, which returns only a raw pointer.
• Non. UnsafeCell<T> only allows code that would otherwise need unsafe blocks to be written in safe code.

संदर्भ

क्यू35. Generics are useful when you _.

• need to reduce code duplication by concretizing values and restricting parameters in functions
• need to reduce code duplication by abstracting values further, such as in function parameters
• need a supertrait
• are not sure if you need a specific kind of trait

प्र36. How do you create a Rust project on the command-line?

• cargo new
• rustup init
• cargo start
• rust new-project

प्रश्न37. Calling.clone() _.

• deeply copies heap data and clones ownership
• clones the pointer to the heap
• clones the heap data onto the stack
• deeply copies heap and stack

संदर्भ

प्रश्न 38. what is one of the roles of the let keyword?

let text = String::new("LinkedIn");

• Create a text object.
• Assign a mutable value.
• request to borrow a string.
• Assign an immutable value.

संदर्भ

प्र39. How is a new enum initialized?

enum Option_i32 {
    Some(i32),
    None,
}

• let integer = Option_i32::कुछ(5);
• let integer = Option_i32.new(कुछ(5))
• let integer = Option_i32::नया::(कुछ(5))
• let integer = Option_i32.init()

संदर्भ

क्यू40. What are the main difference between const and static?

• They can be used interchangeably, but const only supports primitive types while static must be used for structs and user-defined types.
• They can be used interchangeably, but const values are compiled at compile time.
• Values defined with const live in the stack, while static values live on the heap.
• Values defined with const can be copied to wherever they are needed, whereas static values remain in a fixed place in memory.

संदर्भ

प्र41. Which Rust data type represents a signed integer that has the same width as a pointer of the compile target’s CPU?

• i64
• int64
• isize
• int यहाँ

संदर्भ

प्र42. When are supertraits needed?

• when a trait is needed for multiple structs
• when a trait depends on another trait
• only when a generic trait is used
• when a metatrait is needed to use another trait

संदर्भ

प्रश्न 43. Which types are legal for x to be in this snippet?

if x {
    println!("ok");
}

• every type that implements the std::cmp::Truth trait
• only the primitive bool type
• both bool and u8 (which is how bool is implemented under the hood)
• bool and std::sync::atomic::AtomicBool

संदर्भ

प्रश्न 44. How do you access the married data in this struct?

struct person = Person {
    height: u64,
    weight: u64,
    married: bool
}

• person.getMarried()
• व्यक्ति[married]
• person.value(married)
• person.married

संदर्भ

क्यू45. To mark a function as visible to other crates, what do you need to do to its definition?

• Add the public keyword.
• Add the pub keywork.
• Begin the function’s name with a capital letter.
• Remove the private keyword.

संदर्भ

प्र46. Which choice is a compound data type?

• char
• टपल
• bool
• i32

संदर्भ

प्रश्न 47. How could you make this function compile?

fn main() {
    let x = 5;
    println!("The value of x is: {}", x);
    x = 6;
    println!("The value of x is: {}", x);
}

• Use x only once in a println!() कथन.
• Place curly brackets around let x = 5.
• Add const to let x = 6.
• Add mut to let x = 5.

संदर्भ

प्रश्न 48. Using .unwrap() will _.

• let you choose the expected panic error message
• call panic! if there is an error or absence of value
• unwrap the value inside an unsafe wrapper
• return the error inside Ok()

संदर्भ

प्र49. When should the panic! macro be called instead of using std::result::Result?

• when there is a way to encode the information in types used
• when your code is expected to end in a good state
• when the situation is considered unrecoverable
• when valid values are passed on the code

संदर्भ

क्यू50. Which statement about arrays is true?

• [; size of array] can initialize arrays.
• Indexing, such as array.0, accesses elements in arrays.
• A data structure for collections can contain different types of values.
• Arrays are useful when you want to allocate data on the heap and then on the stack.

संदर्भ

प्रश्न51. How would you select the value 2.0 from this tuple?

let pt = Point2D(-1.0, 2.0)

• pt[1]
• pt(1)
• pt.iter().nth(1)
• pt.1

संदर्भ

प्रश्न52. When writing tests, which macro should you use to assert equality between two values?

• assert_eq!()
• assert_equal!()
• is_equals!()
• assert!()

संदर्भ

प्रश्न53. Which code statement in Rust is used to define a BTreeMap object?

• let btm=BTreeMap::नया()
• let mut btm=BTreeMap::नया()
• BTreeMap btm = BTreeMap.new()
• BTreeMap btm = std::संग्रह::BTreeMap::नया()

संदर्भ

Q54 .Rust is known to be memory safe. Which feature is the main reason for the memory safety of Rust?

• ownership
• borrowing
• lifetimes
• संदर्भ

संदर्भ

प्रश्न55 . To support Dynamic Sized variables, what should we use in place of “f32”?

• Not supportedin Rust
• use array
• ?sized
• list all data-types

संदर्भ

प्रश्न56 . क्या है “Drop” in Rust used for?

• run code as multi-threaded
• run code when variable is out of scope
• run code and drop it if error comes
• विकल्प 4

संदर्भ

प्रश्न57 . In Rust, how is a macro from the above Rust code snippet used?

• foo(एक्स)
• #foo
• foo!()
• foo

संदर्भ

प्र 58 . Which library does Rust use for memory allocation?

• tcmalloc
• mimalloc
• ptmalloc
• jemalloc

संदर्भ

प्रश्न59 . Who designed Rust from scratch in 2006?

• Graydon Hoare
• Yukihiro Matsumoto
• Guido Van Rossum
• David flanagan

संदर्भ

क्यू 60. Which types are नहीं allowed within an enum variant’s body?

• zero-sized types
• structs
• trait objects
• floating-point numbers

प्रश्न 61. Which example correctly uses std::संग्रह::HashMap’s Entry API to populate counts?

use std::collections::HashMap;
fn main() {
    let mut counts = HashMap::new();
    let text = "LinkedIn Learning";
    for c in text.chars() {
        // Complete this block
    }
    println!("{:?}", counts);
}

• ­

for c in text.chars() {
    if let Some(count) = &mut counts.get(&c) {
        counts.insert(c, *count + 1);
    } else {
        counts.insert(c, 1);
    };
}

• ­

for c in text.chars() {
    let count = counts.entry(c).or_insert(0);
    *count += 1;
}

• ­

for c in text.chars() {
    let count = counts.entry(c);
    *count += 1;
}

• ­

for c in text.chars() {
    counts.entry(c).or_insert(0).map(|x| x + 1);
}

प्रश्न 62. To convert a Result to an Option, which method should you use?

• .as_option()
• .ok()
• .to_option()
• .into()

प्रश्न 63. Which statement about this code is true?

fn main() {
    let c = 'z';
    let heart_eyed_cat = '😻';
}

• Both are character literals.
• heart_eyed_cat is an invalid expression.
• c is a string literal and heart_eyed_cat is a character literal.
• Both are string literals.

प्रश्न 64. What is an alternative way of writing slice that produces the same result?

...
let s = String::form("hello");
let slice = &s[0..2];

• let slice = &एस[len + 2];
• let slice = &एस[len – 2];
• let slice = &s.copy(0..2);
• let slice = &एस[..2];

प्रश्न 65. How would you select the value 2.0 from this tuple?

let pt = Point2D(-1.0, 2.0)

• pt[1]
• pt(1)
• pt.iter().nth(1)
• pt.1

प्रश्न 66. What is the purpose of the move keyword in Rust?

• To indicate that a value should be moved instead of copied.
• To indicate that a value should be copied instead of moved.
• To indicate that a value should be borrowed instead of owned.
• To indicate that a value should be owned instead of borrowed.

संदर्भ