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use std::error::Error;
use std::fmt;
use std::io;
use std::process;
#[derive(Debug)]
struct UnknownOperatorError;
impl Error for UnknownOperatorError {}
impl fmt::Display for UnknownOperatorError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "invalid operator!")
}
}
fn get_input() -> String {
let mut res = String::new();
io::stdin()
.read_line(&mut res)
.expect("failed to get input!");
return (*res).trim().to_string();
}
fn get_number() -> f32 {
get_input()
.parse::<f32>()
.expect("failed to get your number (possible lack of rizz)")
}
fn calculate(operator: &String, number1: &f32, number2: &f32) -> Result<f32, UnknownOperatorError> {
match operator.as_str() {
"+" => Ok(number1 + number2),
"-" => Ok(number1 - number2),
"/" => Ok(number1 / number2),
"*" => Ok(number1 * number2),
_ => Err(UnknownOperatorError),
}
}
fn main() {
println!("enter a number: ");
let number1 = get_number();
println!("enter an operator: ");
let operator = get_input();
println!("enter another number: ");
let number2 = get_number();
let res = calculate(&operator, &number1, &number2);
match res {
Ok(i) => println!("{i}"),
Err(e) => {
eprintln!("{e}");
process::exit(1);
}
}
}
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