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Fixed mistakes and missing semicolon in enum

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This commit is contained in:
Tanish-Eagle
2022-04-20 22:16:19 +05:30
parent ef190d9e76
commit c241eebbb6
1 changed files with 19 additions and 19 deletions
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38
en/src/compound-types/enum.md
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@ -3,7 +3,7 @@
```rust,editable ```rust,editable
// fix the errors // Fix the errors
enum Number { enum Number {
Zero, Zero,
One, One,
@ -25,18 +25,18 @@ enum Number2 {
fn main() { fn main() {
// a enum variant can be converted to a integer by `as` // An enum variant can be converted to a integer by `as`
assert_eq!(Number::One, Number1::One); assert_eq!(Number::One, Number1::One);
assert_eq!(Number1::One, Number2::One); assert_eq!(Number1::One, Number2::One);
println!("Success!") println!("Success!");
} }
``` ```
2. 🌟 each enum variant can hold its own data. 2. 🌟 Each enum variant can hold its own data.
```rust,editable ```rust,editable
// fill in the blank // Fill in the blank
enum Message { enum Message {
Quit, Quit,
Move { x: i32, y: i32 }, Move { x: i32, y: i32 },
@ -45,17 +45,17 @@ enum Message {
} }
fn main() { fn main() {
let msg1 = Message::Move{__}; // instantiating with x = 1, y = 2 let msg1 = Message::Move{__}; // Instantiating with x = 1, y = 2
let msg2 = Message::Write(__); // instantiating with "hello, world!" let msg2 = Message::Write(__); // Instantiating with "hello, world!"
println!("Success!") println!("Success!");
} }
``` ```
3. 🌟🌟 we can get the data which a enum variant is holding by pattern match 3. 🌟🌟 We can get the data which an enum variant is holding by pattern match.
```rust,editable ```rust,editable
// fill in the blank and fix the error // Fill in the blank and fix the error
enum Message { enum Message {
Quit, Quit,
Move { x: i32, y: i32 }, Move { x: i32, y: i32 },
@ -72,7 +72,7 @@ fn main() {
panic!("NEVER LET THIS RUN！"); panic!("NEVER LET THIS RUN！");
} }
println!("Success!") println!("Success!");
} }
``` ```
@ -80,7 +80,7 @@ fn main() {
```rust,editable ```rust,editable
// fill in the blank and fix the errors // Fill in the blank and fix the errors
enum Message { enum Message {
Quit, Quit,
Move { x: i32, y: i32 }, Move { x: i32, y: i32 },
@ -105,11 +105,11 @@ fn show_message(msg: Message) {
} }
``` ```
5. 🌟🌟 As there is no `null` in Rust, we have to use enum `Option<T>` to deal the cases when value is absent. 5. 🌟🌟 Since there is no `null` in Rust, we have to use enum `Option<T>` to deal with the cases when the value is absent.
```rust,editable ```rust,editable
// fill in the blank to make the `println` work. // Fill in the blank to make the `println` work.
// also add some code to prevent the `panic` from running. // Also add some code to prevent the `panic` from running.
fn main() { fn main() {
let five = Some(5); let five = Some(5);
let six = plus_one(five); let six = plus_one(five);
@ -118,7 +118,7 @@ fn main() {
if let __ = six { if let __ = six {
println!("{}", n); println!("{}", n);
println!("Success!") println!("Success!");
} }
panic!("NEVER LET THIS RUN！"); panic!("NEVER LET THIS RUN！");
@ -133,7 +133,7 @@ fn plus_one(x: Option<i32>) -> Option<i32> {
``` ```
6. 🌟🌟🌟🌟 implement a `linked-list` via enums. 6. 🌟🌟🌟🌟 Implement a `linked-list` via enums.
```rust,editable ```rust,editable
@ -166,12 +166,12 @@ impl List {
// depends on the variant of `self` // depends on the variant of `self`
// `self` has type `&List`, and `*self` has type `List`, matching on a // `self` has type `&List`, and `*self` has type `List`, matching on a
// concrete type `T` is preferred over a match on a reference `&T` // concrete type `T` is preferred over a match on a reference `&T`
// after Rust 2018 you can use self here and tail (with no ref) below as well, // After Rust 2018 you can use self here and tail (with no ref) below as well,
// rust will infer &s and ref tail. // rust will infer &s and ref tail.
// See https://doc.rust-lang.org/edition-guide/rust-2018/ownership-and-lifetimes/default-match-bindings.html // See https://doc.rust-lang.org/edition-guide/rust-2018/ownership-and-lifetimes/default-match-bindings.html
match *self { match *self {
// Can't take ownership of the tail, because `self` is borrowed; // Can't take ownership of the tail, because `self` is borrowed;
// instead take a reference to the tail // Instead take a reference to the tail
Cons(_, ref tail) => 1 + tail.len(), Cons(_, ref tail) => 1 + tail.len(),
// Base Case: An empty list has zero length // Base Case: An empty list has zero length
Nil => 0 Nil => 0