2023 - Day 1 part 1 - rust

2023/1/1.rs

@@ -0,0 +1,31 @@
+use std::io::{BufRead, BufReader};
+use std::fs::File;
+
+fn main (){
+    // let filename = "./input_example.txt";
+    let filename = "./input.txt";
+    let file = BufReader::new(File::open(filename).expect("Unable to open file"));
+    let mut accum: u32 = 0;
+
+    for line in file.lines() { 
+        let mut first_num: char = 'z';
+        let mut last_num: char = 'z';
+        // println!("{}", line.unwrap());
+        for c in line.unwrap().to_string().chars() {
+            if '0' <= c && c <= '9' {
+                if first_num == 'z' {
+                    first_num = c;
+                }
+                last_num = c;
+            }
+        }
+
+        let mut line_num = String::from(first_num);
+        line_num.push(last_num);
+        // println!("first: {}, last: {}", first_num, last_num);
+        // println!("line_num: {}", line_num);
+        accum += line_num.parse::<u32>().unwrap();
+    }
+
+    println!("Total lines are: {}", accum);
+}