# Prime Number in Rust

Published on 31 October 2019 (Updated: 08 May 2023)

Welcome to the Prime Number 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

``````//  Requirement     https://sample-programs.therenegadecoder.com/projects/prime-number/
// Accept a number on command line and print if it is Composite or Prime
// Works till  39 digits, ...

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

fn usage() -> ! {
println!("Usage: please input a non-negative integer");
exit(0);
}

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

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

// Exit if 1st command-line argument not an positive integer
let input_num: u128 = args
.next()
.and_then(|s| parse_int(&s).ok())
.unwrap_or_else(|| usage());

if input_num < 2 || (input_num != 2 && input_num % 2 == 0) {
println!("Composite");
exit(0);
}

let mut n = 3u128;
while n * n <= input_num {
if input_num % n == 0 {
println!("Composite");
exit(0);
}
n += 2;
}
println!("Prime");
}

``````

Prime Number in Rust was written by:

• Mallikarjuna S J
• rzuckerm

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

## 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.