Positive and Negative Number Checker in Rust

In this article I would like to share with you a sample program that will ask the user to give an integer number and then our program will check whether the given number by our user is positive or negative number using Rust as our programming language.

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Sample Program Output

Program Listing

// Positive and Negative Number Checker in Rust Programming language.

// Written By: Mr. Jake R. Pomperada, MAED-IT

// July 28, 2016

use std::io::{self, Write};

use std::fmt::Display;

use std::process;

fn main() {

       println!("\n");

       println!("\tPositve and Negative Number Checker in Rust");

       println!("\n");

    let number_value: i32 = grab_input("Enter a Number ")

        .unwrap_or_else(|e| exit_err(&e, e.raw_os_error().unwrap_or(-1)))

        .trim()

        .parse()

        .unwrap_or_else(|e| exit_err(&e, 2));

   if number_value >= 0 {

    println!("\n"); 

    println!("The number {} is a POSITIVE NUMBER.",number_value);

  }

 else {

    println!("\n");

    println!("The number {} is a NEGATIVE NUMBER.",number_value);

   }

    println!("\n"); 

    println!("End of Program");

}

fn grab_input(msg: &str) -> io::Result<String> {

    let mut buf = String::new();

    print!("{}: ", msg);

    try!(io::stdout().flush());

    try!(io::stdin().read_line(&mut buf));

    Ok(buf)

}

fn exit_err<T: Display>(msg: T, code: i32) -> ! {

    let _ = writeln!(&mut io::stderr(), "Error: {}", msg);

    process::exit(code)

}