123 lines
1.8 KiB
Markdown
123 lines
1.8 KiB
Markdown
1.
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```rust
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fn main() {
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// don't modify the following two lines!
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let (x, y) = (1, 2);
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let s = sum(x, y);
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assert_eq!(s, 3);
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}
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fn sum(x: i32, y: i32) -> i32 {
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x + y
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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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print();
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}
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// replace i32 with another type
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fn print() -> () {
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println!("hello,world");
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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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never_return();
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}
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fn never_return() -> ! {
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// implement this function, don't modify fn signatures
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panic!("I return nothing!")
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}
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```
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```rust
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fn main() {
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never_return();
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}
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use std::thread;
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use std::time;
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fn never_return() -> ! {
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// implement this function, don't modify fn signatures
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loop {
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println!("I return nothing");
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// sleeping for 1 second to avoid exhausting the cpu resoucre
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thread::sleep(time::Duration::from_secs(1))
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}
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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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println!("Success!");
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}
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fn get_option(tp: u8) -> Option<i32> {
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match tp {
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1 => {
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// TODO
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}
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_ => {
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// TODO
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}
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};
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never_return_fn()
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}
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// IMPLEMENT this function
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// DON'T change any code else
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fn never_return_fn() -> ! {
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unimplemented!()
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}
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```
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```rust
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// IMPLEMENT this function in THREE ways
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fn never_return_fn() -> ! {
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panic!()
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}
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```
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```rust
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// IMPLEMENT this function in THREE ways
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fn never_return_fn() -> ! {
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loop {
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std::thread::sleep(std::time::Duration::from_secs(1))
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}
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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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// FILL in the blank
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let b = false;
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let v = match b {
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true => 1,
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// Diverging functions can also be used in match expression
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false => {
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println!("Success!");
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panic!("we have no value for `false`, but we can panic")
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}
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};
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println!("Exercise Failed if printing out this line!");
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}
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``` |