hello rust functions / published by https://github.com/dacr/code-examples-manager #aeec4fd7-defa-45d9-911f-8cbcf68a9727/a81d64efb9217ee5f21b07a3ea2688b364af49fd

hello-functions.rs

#!/usr/bin/env rust-script
// summary : hello rust functions
// keywords : rust, functions, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : aeec4fd7-defa-45d9-911f-8cbcf68a9727
// created-on : 2024-10-12T23:11:09+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : ./$file

// -------------------------------------------------------------------------------------------------
fn ident(n: i32) -> i32 {
    n
}

fn sum(x: i32, y: i32) -> i32 {
    x + y
}

fn show(x: i32, y: i32) -> () { // -> () is optional
    println!("x: {}, y: {}", x, y);
}

// -------------------------------------------------------------------------------------------------
fn fact_recurs(x: i32, accu: i128) -> i128 {
    if x <= 1 {
        accu
    } else {
        fact_recurs(x - 1, accu * i128::from(x))
    }
}

fn fact(x: i32) -> i128 {
    fact_recurs(x, 1)
}

// -------------------------------------------------------------------------------------------------

fn main() {
    show(ident(42), sum(40, 2));
    let x = 23;
    println!("{}! = {}", x, fact(x))
}