Functions
// Copyright 2023 Google LLC
// SPDX-License-Identifier: Apache-2.0
fn gcd(a: u32, b: u32) -> u32 {
if b > 0 { gcd(b, a % b) } else { a }
}
fn main() {
dbg!(gcd(143, 52));
}
This slide should take about 3 minutes.
- Declaration parameters are followed by a type (the reverse of some programming languages), then a return type.
- The last expression in a function body (or any block) becomes the return value. Simply omit the
;at the end of the expression. Thereturnkeyword can be used for early return, but the “bare value” form is idiomatic at the end of a function (refactorgcdto use areturn). - Some functions have no return value, and return the ‘unit type’,
(). The compiler will infer this if the return type is omitted. - Overloading is not supported – each function has a single implementation.
- Always takes a fixed number of parameters. Default arguments are not supported. Macros can be used to support variadic functions.
- Always takes a single set of parameter types. These types can be generic, which will be covered later.