Programming Fundamentals/Functions/Rust

functions.rs

// This program asks the user for a Fahrenheit temperature, 
// converts the given temperature to Celsius,
// and displays the results.
//
// References:
// https://www.geeksforgeeks.org/standard-i-o-in-rust/
// https://www.includehelp.com/rust/read-a-float-number-from-the-user.aspx
// https://doc.rust-lang.org/book/ch03-03-how-functions-work.html

use std::io;

fn main() {
    let fahrenheit = get_fahrenheit();
    let celsius = calculate_celsius(fahrenheit);
    display_result(fahrenheit, celsius);
}

fn get_fahrenheit() -> f32 {
    println!("Enter Fahrenheit temperature:");
    let mut line = String::new();
    io::stdin().read_line(&mut line).expect("Error reading line");
    let fahrenheit:f32 = line.trim().parse().expect("Not a valid number");
    return fahrenheit;
}

fn calculate_celsius(fahrenheit:f32) -> f32 {
    let celsius = (fahrenheit - 32.0) * 5.0 / 9.0;
    return celsius;    
}

fn display_result(fahrenheit:f32, celsius:f32) {
    println!("{}° Fahrenheit is {}° Celsius", fahrenheit, celsius);
}

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functions.rs

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See Also