2023-01: Working part 1

.gitignore

@@ -0,0 +1,14 @@
+# Generated by Cargo
+# will have compiled files and executables
+debug/
+target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb

2023/01-trebuchet/input_test.txt

@@ -0,0 +1,4 @@
+1abc2
+pqr3stu8vwx
+a1b2c3d4e5f
+treb7uchet

2023/01-trebuchet/src/main.rs

@@ -1,3 +1,6 @@
+mod part_one;
+
 fn main() {
-    println!("Hello, world!");
+    part_one::part_one();
+    //part_two();
 }

2023/01-trebuchet/src/part_one.rs

@@ -0,0 +1,49 @@
+// https://doc.rust-lang.org/stable/rust-by-example/std_misc/file/read_lines.html
+use std::fs::File;
+use std::io::{self, BufRead};
+use std::path::Path;
+
+
+pub fn part_one() {
+    if let Ok(lines) = read_lines("./input.txt") {
+
+        let mut result = 0;
+
+        for line in lines {
+            result += parse_line(&line.unwrap());
+        }
+
+        println!("{}", result);
+    }
+}
+
+
+
+fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
+where P: AsRef<Path>, {
+    let file = File::open(filename)?;
+    Ok(io::BufReader::new(file).lines())
+}
+
+fn parse_line(s: &str) -> u32{
+
+    const RADIX: u32 = 10;
+    
+    let mut first_digit = 0;
+    let mut last_digit = 0;
+
+    for c in s.chars() {
+        if c.is_digit(RADIX) {
+
+            let digit = c.to_digit(RADIX).unwrap();
+
+            if first_digit == 0 {
+                first_digit = digit;
+            }
+            last_digit = digit;
+            
+        }
+    }
+    
+    return first_digit * 10 + last_digit   
+}