ownership

Question 1

The exact lifetime of each value is controlled by the programmer. Yes or No?

Answer 1

Yes.

Question 2

Will the compiler check the lifetime of values?

Answer 2

yes.

Question 3

Does the Rust ownership mechanism prevent dangling pointers?

Answer 3

yes.

Question 4

Does rust provide a nil value?

Answer 4

No.

Question 5

In rust, every value has exactly __ owner

Answer 5

one.

Question 6

when the owner is freed, the value is __

Answer 6

dropped.

Question 7

Does Rust use a Garbage Collector?

Answer 7

No

Question 8

T or F. Each value in rust has a variable that is its owner.

Answer 8

True. Except rc

Question 9

What are the three ownership rules?

Answer 9

1. Each value has exactly one owner
2. Owners can change, but there can only be one at any instant.
3. When the owner goes out of scope, the value is dropped.

Question 10

What is the restriction for mutable references?

Answer 10

There can be only one mutable reference. There cannot be a mix of mutable and unmutable

Question 11

What must references always be?

Answer 11

Valid. The must always reference something.

Question 12

What is the syntax for making a string slice?

Answer 12

let s = “test”.to_string();
let slice = s[..3]; //first three bytes
//0,1,2 chars were copied. Not 3

Question 13

What is the Rust concept of Move

Answer 13

Moving ownership. Assignment will move ownership.

Question 14

let x = 3; 
let y = 3; 
println!("{}", x) // will this work? why ? 
let x = "blaster".to_string()
y = x 
println!("{}", x) // will this work? why ?

Answer 14

printing the integer will work because integers implement Copy trait. This means they aren’t moved by assignment, but copied on the stack. However, std::string types aren’t copied, they are moved. The second print won’t compile.