Day 7 parse input

day_07/small_input.txt

@@ -0,0 +1,9 @@
+190: 10 19
+3267: 81 40 27
+83: 17 5
+156: 15 6
+7290: 6 8 6 15
+161011: 16 10 13
+192: 17 8 14
+21037: 9 7 18 13
+292: 11 6 16 20

day_07/src/main.rs

@@ -1,3 +1,77 @@
-fn main() {
+// https://adventofcode.com/2024/day/7
-    println!("Hello, world!");
+//
+// Run command: cargo run ./input.txt
+
+use std::{
+    env,
+    error::Error,
+    fs::File,
+    io::{BufReader, prelude::*},
+    path::Component,
+    sync::RwLockWriteGuard,
+};
+
+#[derive(Debug)]
+enum Ops {
+    Multiply,
+    Add,
+}
+
+#[derive(Debug)]
+struct Equation {
+    answer: i32,
+    components: Vec<i32>,
+}
+
+impl Equation {
+    fn new(equation_str: &str) -> Result<Equation, String> {
+        let split_equation: Vec<_> = equation_str.split(":").collect();
+        if split_equation.len() != 2 {
+            return Err(format!("Invalid equation string: {}", equation_str));
+        }
+        let answer = match split_equation[0].parse() {
+            Ok(a) => a,
+            Err(_) => {
+                return Err(format!(
+                    "Error parsing answer {} in equation: {}",
+                    split_equation[0], equation_str
+                ));
+            }
+        };
+        let components = split_equation[1]
+            .split_whitespace()
+            .map(|c| match c.parse::<i32>() {
+                Ok(a) => Ok(a),
+                Err(_) => Err(format!(
+                    "Error parsing component {} in equation: {}",
+                    c, equation_str
+                )),
+            })
+            .collect::<Result<Vec<i32>, String>>()?;
+        Ok(Equation { answer, components })
+    }
+}
+
+fn main() -> Result<(), Box<dyn Error>> {
+    // Handle command input
+    let args: Vec<String> = env::args().collect();
+    if args.len() != 2 {
+        panic!(
+            "{} must be run with a single argument of file name!",
+            &args[0]
+        )
+    }
+    let input_file = &args[1];
+
+    let file = File::open(input_file)?;
+    let buffer = BufReader::new(file);
+
+    let mut equations = Vec::new();
+    for line in buffer.lines() {
+        let line = line?;
+        equations.push(Equation::new(&line)?)
+    }
+
+    println!("{:?}", equations);
+    Ok(())
 }