add day 1, part 1

day01/part1.rs

@@ -0,0 +1,57 @@
+// Copyright 2023 Christian Ulrich
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// usage: ./part1 < input
+
+use std::io;
+
+pub struct CalibrationValues {
+    inner: Vec<Vec<char>>,
+}
+
+impl CalibrationValues {
+    pub fn from_stdin() -> Result<Self, &'static str> {
+        let mut values = vec![];
+        for line in io::stdin().lines() {
+            let digits = line
+                .unwrap()
+                .chars()
+                .filter(|c| c.is_digit(10))
+                .collect::<Vec<_>>();
+            if digits.len() > 0 {
+                values.push(digits);
+            }
+        }
+        Ok(Self { inner: values })
+    }
+
+    pub fn iter(&mut self) -> std::slice::Iter<'_, Vec<char>> {
+        self.inner.iter()
+    }
+}
+
+fn main() -> Result<(), &'static str> {
+    let mut values = CalibrationValues::from_stdin()?;
+    let mut sum = 0;
+    for digits in values.iter() {
+        sum += [*digits.first().unwrap(), *digits.last().unwrap()]
+            .iter()
+            .collect::<String>()
+            .parse::<u32>()
+            .map_err(|_| "cannot parse calibration value")?;
+    }
+    println!("{sum}");
+    Ok(())
+}

day01/testinput

@@ -0,0 +1,5 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet
+