From 53ea6379d9f11ef700644fc8f7f4c0bc0057f5d4 Mon Sep 17 00:00:00 2001 From: Julio Biason Date: Wed, 7 Dec 2022 14:47:03 -0300 Subject: [PATCH] With iterator! --- day1/src/main.rs | 57 ++++++++++++++++++++++++++++++++---------------- 1 file changed, 38 insertions(+), 19 deletions(-) diff --git a/day1/src/main.rs b/day1/src/main.rs index ceda7ac..062dbea 100644 --- a/day1/src/main.rs +++ b/day1/src/main.rs @@ -1,10 +1,47 @@ use std::fs::File; use std::io::BufRead; use std::io::BufReader; +use std::io::Lines; use clap::Arg; use clap::Command; +struct Accumulator { + lines: Lines, + current: u32, +} + +trait Elvish { + fn elf(self) -> Accumulator; +} + +impl Elvish for Lines { + fn elf(self) -> Accumulator { + Accumulator { + lines: self, + current: 0, + } + } +} + +impl Iterator for Accumulator { + type Item = u32; + + fn next(&mut self) -> Option { + while let Some(Ok(line)) = self.lines.next() { + let line = line.trim(); + if line.is_empty() { + let result = self.current; + self.current = 0; + return Some(result); + } else { + self.current += line.parse::().unwrap(); + } + } + None + } +} + fn main() { let matches = Command::new("Day1").arg(Arg::new("filename")).get_matches(); let filename = matches @@ -15,23 +52,5 @@ fn main() { let file = File::open(filename).expect("Can't read file"); let reader = BufReader::new(file); - let mut max_calories = 0; - let mut elf_calories = 0; - - for line in reader.lines() { - let line = line.unwrap(); - let line = line.trim(); - - // XXX I want to do this with an iterator! - if line.is_empty() { - if elf_calories > max_calories { - max_calories = elf_calories; - } - elf_calories = 0; - } else { - println!("Line: {}", line); - elf_calories += line.parse::().unwrap(); - } - } - println!("Max: {}", max_calories); + println!("Max: {:?}", reader.lines().elf().max()) }