rustlings/exercises/error_handling/errors3.rs

50 lines
867 B
Rust

// errors3.rs
// This is a program that is trying to use a completed version of the
// `total_cost` function from the previous exercise. It's not working though!
// Why not? What should we do to fix it? Scroll for hints!
// I AM NOT DONE
use std::num::ParseIntError;
fn main() {
let mut tokens = 100;
let pretend_user_input = "8";
let cost = total_cost(pretend_user_input)?;
if cost > tokens {
println!("You can't afford that many!");
} else {
tokens -= cost;
println!("You now have {} tokens.", tokens);
}
}
pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
let processing_fee = 1;
let cost_per_item = 5;
let qty = item_quantity.parse::<i32>()?;
Ok(qty * cost_per_item + processing_fee)
}
// If other functions can return a `Result`, why shouldn't `main`?