day1 part2 :(

src/day1.rs

@@ -10,6 +10,7 @@ pub fn part1(input: &str) -> i32 {
     dial_counter.zero_count
 }
 
+#[derive(Debug)]
 struct DialCounter {
     position: i32,
     zero_count: i32,
@@ -26,7 +27,79 @@ impl DialCounter {
             self.zero_count = self.zero_count + 1;
         }
     }
+
+    fn rotate_2(&mut self, operation: &str) {
+        let direction = operation.chars().nth(0).unwrap();
+        let magnitude = operation[1..].parse::<i32>().unwrap();
+        match direction {
+            'L' => {
+                if self.position == 0 {
+                    self.position = 100
+                }
+                self.position = self.position - magnitude;
+                while self.position < 0 {
+                    self.position = self.position + 100;
+                    self.zero_count = self.zero_count + 1;
+                }
+                if self.position == 0 {
+                    self.zero_count = self.zero_count + 1;
+                }
+            }
+            'R' => {
+                self.position = self.position + magnitude;
+                while self.position > 99 {
+                    self.position = self.position - 100;
+                    self.zero_count = self.zero_count + 1;
+                }
+            }
+            _ => panic!("Unexpected input!"),
+        };
+    }
+}
+
+#[aoc(day1, part2)]
+pub fn part2(input: &str) -> i32 {
+    let mut dial_counter = DialCounter {
+        position: 50,
+        zero_count: 0,
+    };
+    for line in input.lines() {
+        dial_counter.rotate_2(line)
+    }
+    dial_counter.zero_count
 }
 
 #[cfg(test)]
-mod tests {}
+mod tests {
+    use super::*;
+
+    struct Setup {
+        test_string_1: String,
+        test_string_2: String,
+    }
+
+    impl Setup {
+        fn new() -> Self {
+            Self {
+                test_string_1: String::from("L68\nL30\nR48\nL5\nR60\nL55\nL1\nL99\nR14\nL82\n"),
+                test_string_2: String::from("R27\nL477\n"),
+            }
+        }
+    }
+
+    #[test]
+    fn test_part1() {
+        let setup = Setup::new();
+        assert_eq!(part1(&setup.test_string_1), 3);
+        println!(" ");
+        assert_eq!(part1(&setup.test_string_2), 1);
+    }
+
+    #[test]
+    fn test_part2() {
+        let setup = Setup::new();
+        assert_eq!(part2(&setup.test_string_1), 6);
+        println!(" ");
+        assert_eq!(part2(&setup.test_string_2), 5);
+    }
+}