day_03 init

day_03/Cargo.toml

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+[package]
+name = "day_03"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

day_03/src/main.rs

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+use std::fs::File;
+use std::io::{self, BufRead};
+use std::path::Path;
+
+fn main() {
+    // File input must exist in the current path
+    if let Ok(lines) = read_lines("./input") {
+        let mut total_part_1: u64 = 0;
+        let mut total_part_2: u64 = 0;
+
+        // Consumes the iterator, returns an (Optional) String
+        for line in lines {
+            if let Ok(mut l) = line {
+                // Part 1
+
+                // Part 2
+
+            }
+        }
+
+        println!("Total of part 1 is {}", total_part_1);
+        println!("Total of part 2 is {}", total_part_2);
+    }
+}
+
+// The output is wrapped in a Result to allow matching on errors
+// Returns an Iterator to the Reader of the lines of the file.
+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())
+}