Fibonacci in Rust

Welcome to the Fibonacci in Rust page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

use std::env::args;
use std::process::exit;
use std::str::FromStr;

const LIMIT: i32 = 93;

fn usage() -> ! {
    println!("Usage: please input the count of fibonacci numbers to output");
    exit(0);
}

fn parse_int<T: FromStr>(s: &str) -> Result<T, <T as FromStr>::Err> {
    s.trim().parse::<T>()
}

fn fibonacci(terms: i32) {
    if terms > LIMIT {
        println!("The number of terms you want to calculate is too big!");
        println!("The limit is {}.", LIMIT);
    } else {
        let mut a = 0u64;
        let mut b = 1u64;
        for i in 1..(terms + 1) {
            (a, b) = (b, a + b);
            println!("{i}: {a}");
        }
    }
}

fn main() {
    let mut args = args().skip(1);

    // Exit if 1st command-line argument not an integer
    let mut input_num: i32 = args
        .next()
        .and_then(|s| parse_int(&s).ok())
        .unwrap_or_else(|| usage());

    // Show request number of Fibonacci numbers
    fibonacci(input_num);
}

Fibonacci in Rust was written by:

• Noah Nichols
• rzuckerm

If you see anything you'd like to change or update, please consider contributing.

Note: The solution shown above is the current solution in the Sample Programs repository as of May 08 2023 19:53:07. The solution was first committed on Oct 05 2018 09:33:10. As a result, documentation below may be outdated.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.