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Structs in Rust are user-defined data types. They contain fields that are used to define their particular instance.We defined structs with the help of the struct keyword followed by the name we want for the struct. The name of the struct should describe the significance of the pieces of data that we are grouping together inside it.Syntaxstruct Employee { id: i32, name: String, leaves: i8, }The above syntax contains the name of the struct and inside the curly braces, we have different fields, namely, id which is of type i32, name and leaves.Creating an InstanceTo create an ... Read More
Slices in Rust are a collection of elements of the same data type T, but unlike arrays, it is not necessary that their length is known at compile time.In Rust, a slice is a two-word object, where the first word is actually a pointer to the data and the second word is simply the length of the slice.Slices are much safer to use than arrays, and they allow efficient access to an array without copying. Slices are created from an array, string. They can be both mutable and not. A slice generally refers to slice of an array or a ... Read More
Path struct in Rust is used to represent the file paths in the underlying filesystem. It should also be noted that a Path in Rust is not represented as a UTF-8 string; instead, it is stored as a vector of bytes (Vec).ExampleConsider the example shown below − Live Demouse std::path::Path; fn main() { // Create a `Path` from an `&'static str` let path = Path::new("."); // The `display` method returns a `Show`able structure let display = path.display(); // Check if the path exists if path.exists() { println!("{} exists", display); } ... Read More
Handling critical errors in Rust is done with the help of panic! Macro. There are other ways to handle errors in Rust, but panic is unique in the sense that it is used to deal with unrecoverable errors.When we execute the panic! Macro, the whole program unwinds from the stack, and hence, it quits. Because of this manner with which the program quits, we commonly use panic! for unrecoverable errors.SyntaxThe syntax of calling a panic looks like this −panic!("An error was encountered");We usually pass a custom message inside the parentheses.ExampleConsider the code shown below as a reference − Live Demofn drink(beverage: ... Read More
Rust provides us with a match keyword that can be used for pattern matching. It is similar to the switch statement in C, and the first arm that matches is evaluated.ExampleConsider the example shown below −fn main() { let number = 17; println!("Tell me about {}", number); match number { 1 => println!("One!") 2 | 3 | 5 | 7 | 11 => println!("A prime"), 13..=19 => println!("A teen"), _ => println!("Ain't special"), } }In the above example, we are trying to use a ... Read More
Rust provides a loop keyword that allows us to run an infinite loop. The infinite loop indicated by the help of the loop keyword can be broken by the use of the break keyword. Also, we can exit an iteration and continue the infinite loop with the help of the continue keyword.ExampleConsider the example shown below − Live Demofn main() { let mut count = 0u32; println!("Infinite loop begins!!"); // Infinite loop loop { count += 1; if count == 4 { println!("four"); ... Read More
HashMap is an important data structure, as it allows us to store data in key-value pairs. In Rust, HashMap stores values by key.HashMap keys can be Boolean, Integer, strings or any other data type that implements the Eq and Hash traits.HashMaps can grow in size, and when the space becomes too excessive, they can also shrink themselves.We can create a HashMap in multiple ways, we can use either HashMap::with_capacity(uint) or HashMap::new().Following are the methods that HashMaps support:insert()get()remove()iter()ExampleLet’s see an example where we build a HashMap and use all these operations stated above.Consider the example shown below. Live Demouse std::collections::HashMap; fn ... Read More
From and Into are two traits that Rust provides us. They are internally linked.From TraitWe make use of From trait when we want to define a trait to how to create itself from any other type. It provides a very simple mechanism with which we can convert between several types.For example, we can easily convert str into a String.ExampleConsider the example shown below: Live Demofn main() { let my_str = "hello"; let my_string = String::from(my_str); println!("{}", my_string); }OutputhelloWe can even convert our own types.ExampleConsider the example shown below:use std::convert::From; #[derive(Debug)] struct Num { value: i64, } impl ... Read More
Also referred to as enumerations, enums are very useful in certain cases. In Rust, we use enums, as they allow us to define a type that may be one of a few different variants.Enumerations are declared with the keyword enum.Example Live Demo#![allow(unused)] #[derive(Debug)] enum Animal { Dog, Cat, } fn main() { let mut b : Animal = Animal::Dog; b = Animal::Cat; println!("{:?}", b); }OutputCatZero-variant EnumsEnums in Rust can also have zero variants, hence the name Zero-variant enums. Since they do not have any valid values, they cannot be instantiated.Zero-variant enums are equivalent to the never ... Read More
Rust provides us with two types of constants. These are −const − an unchangeable valuestatic − possible mutable value with static lifetime.If we try to assign another value to an already declared const value, the compiler will throw an error.ExampleConsider the example shown below − Live Demostatic LANGUAGE: &str = "TutorialsPoint-Rust"; const THRESHOLD: i32 = 10; fn is_small(n: i32) -> bool { n < THRESHOLD } fn main() { // Error! Cannot modify a `const`. THRESHOLD = 5; println!("Everything worked fine!"); }In the above code, we are trying to modify the value of a variable that is ... Read More