39 lines
757 B
Rust
39 lines
757 B
Rust
fn add_one(x: i32) -> i32 {
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x + 1
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}
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/// A function with a function pointer argument
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fn do_twice(f: fn(i32) -> i32, arg: i32) -> i32 {
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f(arg) + f(arg)
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}
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#[derive(Debug)]
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enum Status {
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Value(u32),
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Stop,
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}
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fn returns_closure() -> Box<dyn Fn (i32) -> i32> {
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Box::new(|x| x + 1)
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}
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fn main() {
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let answer = do_twice(add_one, 5);
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println!("The answer is: {}", answer);
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// Tuple Structs set up via function pointers
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let list_of_statuses: Vec<Status> =
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(0u32..20)
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.map(Status::Value)
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.collect();
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println!("List of statuses: {:?}", list_of_statuses);
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let increment = returns_closure();
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let x = 5;
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let y = increment(x);
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println!("The returned closure returns: {}", y);
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}
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