144 lines
1.7 KiB
Markdown
144 lines
1.7 KiB
Markdown
1.
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```rust
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fn main() {
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let x: i32 = 5; // uninitialized but using, ERROR !
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let y: i32; // uninitialized but also unusing, only warning
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println!("{} is equal to 5", x);
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}
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```
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2.
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```rust
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fn main() {
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let mut x = 1;
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x += 2;
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println!("{} is equal to 3", x);
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}
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```
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3.
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```rust
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fn main() {
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let x: i32 = 10;
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let y: i32 = 20;
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{
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let y: i32 = 5;
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println!("The value of x is {} and value of y is {}", x, y);
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}
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println!("The value of x is {} and value of y is {}", x, y);
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}
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```
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4.
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```rust
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fn main() {
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let x = define_x();
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println!("{}, world", x);
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}
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fn define_x() -> String {
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let x = "hello".to_string();
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x
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}
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```
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```rust
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fn main() {
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let x = define_x();
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println!("{:?}, world", x);
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}
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fn define_x() -> &'static str {
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let x = "hello";
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x
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}
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```
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5.
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```rust
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fn main() {
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let x: i32 = 5;
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{
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let x = 12;
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assert_eq!(x, 12);
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}
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assert_eq!(x, 5);
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let x = 42;
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println!("{}", x); // Prints "42".
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}
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```
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6.
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```rust
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fn main() {
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let mut x: i32 = 1;
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x = 7;
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// Shadowing and re-binding
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let x = x;
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let y = 4;
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// Shadowing
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let y = "I can also be bound to text!";
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println!("Success!");
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}
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```
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7.
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```rust
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fn main() {
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let _x = 1;
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}
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```
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```rust
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#[allow(unused_variables)]
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fn main() {
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let x = 1;
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}
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```
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8.
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```rust
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fn main() {
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let (mut x, y) = (1, 2);
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x += 2;
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assert_eq!(x, 3);
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assert_eq!(y, 2);
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}
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```
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```rust
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fn main() {
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let (x, y) = (1, 2);
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let x = 3;
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assert_eq!(x, 3);
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assert_eq!(y, 2);
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}
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```
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9.
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```rust
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fn main() {
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let (x, y);
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(x, ..) = (3, 4);
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[.., y] = [1, 2];
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// fill the blank to make the code work
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assert_eq!([x, y], [3, 2]);
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}
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``` |