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@agarmu

agarmu/tempconv.rs

Created Jul 10, 2020
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use std::io::{stdin, stdout, Write};
use regex::Regex;
use colored::*;
//[dependencies]
//regex = "1"
//colored = "1.9"
fn main() {
let re = Regex::new(r#"(?x)(?P<num>(-?)([0-9]+)(\.)?([0-9]+)?)(?P<ft>(?P<frm>C|K|F)(?P<to>C|K|F))"#)
.unwrap();
help_msg();
loop {
let inp = match input(String::from("> ")) {
Ok(s) => s,
Err(r) => {
eprintln!("{}. Please try again",r);
continue;
}
};
let inp = match inp.trim().parse::<String>() {
Ok(s) => s,
Err(_) => {
println!("Internal error.");
continue;
}
};
match inp.as_str() {
"q" | "quit" | "exit" => {
println!("{}","Thanks for using this calculator.".bright_green().bold().underline());
break;
},
"help" => {
help_msg();
continue;
},
"" => continue,
_ => (),
};
let caps = match re.captures(inp.as_str()){
Some(v) => v,
None => {
eprintln!("{}","Invalid input. Type 'help' for help about input, or 'exit' to exit.".bright_red().bold());
continue;
}
};
let val: f64 = caps["num"].parse().unwrap();
let ans = match &caps["ft"] {
"FC" => f_to_c(val),
"CF" => c_to_f(val),
"CK" => c_to_k(val),
"KC" => k_to_c(val),
"KF" => k_to_f(val),
"FK" => f_to_k(val),
"KK" | "CC" | "FF" => val,
_ => {
eprintln!("{}","Invalid input. Type 'help' for help about input, or 'exit' to exit.".bright_red().bold());
continue;
}
};
println!("{}",format!("{:.2} deg {} = {:.2} deg {}", val, &caps["frm"], ans, &caps["to"]).bright_green().bold().underline());
};
}
fn help_msg() {
println!("{}","Welcome to the temperature converter.".blue());
println!("{}","Enter your temperature as a floating point number, and then two of these letters: ".blue());
println!("{}","\tC : Celsius".yellow().bold());
println!("{}","\tF : Fahrenheit".yellow().bold());
println!("{}","\tK : Kelvin".yellow().bold());
println!("{}","where the first is the one you wish to covert from and the second is the one to convert to.".blue());
println!("{}","For example : 32FC converts 32 deg Fahrenheit to Celsius.".blue());
println!("{}","You can quit by typing 'quit', 'exit',or 'q'; or view this message again by typing 'help'".blue());
}
fn input(prompt: String) -> Result<String,String> {
print!("{}", prompt);
match stdout().flush() {
Ok(_) => (),
Err(_) => return Err(String::from("Failed to read input."))
};
let mut input = String::new();
match stdin().read_line(&mut input) {
Ok(_) => (),
Err(_) => return Err(String::from("Failed to store input."))
};
Ok(input)
}
fn f_to_c (f: f64) -> f64 {
(f - 32.) * 5./9.
}
fn c_to_f (c: f64) -> f64 {
(c * 9./5.) + 32.
}
fn c_to_k (c: f64) -> f64 {
c + 273.15
}
fn k_to_c (k: f64) -> f64 {
k - 273.15
}
fn f_to_k (f: f64) -> f64 {
((f - 32.) * 5./9.) + 273.15
}
fn k_to_f (k: f64) -> f64 {
((k - 273.15) * 9./5.) + 32.
}
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