Start implementing day 4

day_04/small_input.txt

@@ -0,0 +1,10 @@
+MMMSXXMASM
+MSAMXMSMSA
+AMXSXMAAMM
+MSAMASMSMX
+XMASAMXAMM
+XXAMMXXAMA
+SMSMSASXSS
+SAXAMASAAA
+MAMMMXMMMM
+MXMXAXMASX

day_04/src/main.rs

@@ -1,3 +1,72 @@
-fn main() {
+//https://adventofcode.com/2024/day/4
-    println!("Hello, world!");
+//
+// Run command: cargo run ./input.txt
+
+use std::env;
+use std::error::Error;
+use std::fmt::Display;
+use std::fs::File;
+use std::io::{BufReader, prelude::*};
+
+#[derive(Debug)]
+struct Crossword {
+    data: Vec<Vec<char>>,
+    width: usize,
+    height: usize,
+}
+
+impl Crossword {
+    fn new(file: File) -> Result<Crossword, Box<dyn Error>> {
+        let mut input_buffer = BufReader::new(file);
+
+        let mut data: Vec<Vec<char>> = Vec::new();
+
+        let mut first_line = String::new();
+        input_buffer.read_line(&mut first_line)?;
+        let first_line = first_line.trim_end().to_owned();
+        let width = first_line.len();
+        for line in input_buffer.lines() {
+            let line = line?;
+            if line.len() != width {
+                println!("{}", line);
+                Err("Line length of input are not consistent")?;
+            }
+            data.push(line.chars().collect());
+        }
+        let height = data.len();
+
+        Ok(Crossword {
+            data,
+            width,
+            height,
+        })
+    }
+}
+
+impl Display for Crossword {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        for row in &self.data {
+            let row = String::from_iter(row.iter());
+            writeln!(f, "{}", row)?;
+        }
+        Ok(())
+    }
+}
+
+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 files name!",
+            &args[0]
+        )
+    }
+    let input_file_string = &args[1];
+
+    let crossword = Crossword::new(File::open(input_file_string)?)?;
+
+    println!("{}", crossword);
+
+    Ok(())
 }