78 lines
1.7 KiB
Plaintext
78 lines
1.7 KiB
Plaintext
// Unlike C/C++, there's no restriction on the order of function definitions
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fn main() {
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// We can use this function here, and define it somewhere later
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fizzbuzz_to(100);
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}
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// Function that returns a boolean value
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fn is_divisible_by(lhs: u32, rhs: u32) -> bool {
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// Corner case, early return
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if rhs == 0 {
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return false;
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}
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// This is an expression, the `return` keyword is not necessary here
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lhs % rhs == 0
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}
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// Functions that "don't" return a value, actually return the unit type `()`
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fn fizzbuzz(n: u32) -> () {
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if is_divisible_by(n, 15) {
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println!("fizzbuzz");
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} else if is_divisible_by(n, 3) {
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println!("fizz");
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} else if is_divisible_by(n, 5) {
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println!("buzz");
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} else {
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println!("{}", n);
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}
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}
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// When a function returns `()`, the return type can be omitted from the
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// signature
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fn fizzbuzz_to(n: u32) {
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for n in 1..n + 1 {
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fizzbuzz(n);
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}
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}
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async fn async_example(n: u32) {
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for n in 1..n + 1 {
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fizzbuzz(n);
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}
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}
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const fn const_example(n: u32) {
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for n in 1..n + 1 {
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fizzbuzz(n);
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}
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}
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extern "Rust" fn foo() {}
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unsafe fn unsafe_example(n: u32) {
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for n in 1..n + 1 {
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fizzbuzz(n);
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}
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}
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// Declares a function with the "C" ABI
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extern "C" fn new_i32() -> i32 { 0 }
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// Declares a function with the "stdcall" ABI
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extern "stdcall" fn new_i32_stdcall() -> i32 { 0 }
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async fn regular_example() { }
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async unsafe fn unsafe_example() { }
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const fn generic_example<'a>(x: &'a str) -> impl Future<Output = usize> + 'a {
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async move { x.len() }
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}
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fn generic_example2<const N: usize>(arr: [i32; N]) {
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// Used as a type within a function body.
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let x: [i32; N];
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// Used as an expression.
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println!("{}", N * 2);
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}
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