Initial commit

clock/src/lib.rs

@@ -0,0 +1,39 @@
+#[derive(Eq, PartialEq, Debug)]
+pub struct Clock {
+    minutes: i32,
+}
+
+const MINUTES_IN_AN_HOUR: i32 = 60;
+const HOURS_IN_A_DAY: i32 = 24;
+const MINUTES_IN_A_DAY: i32 = HOURS_IN_A_DAY * MINUTES_IN_AN_HOUR;
+
+impl ToString for Clock {
+    fn to_string(&self) -> String {
+        format!("{:02}:{:02}", self.hours(), self.minutes())
+    }
+}
+
+impl Clock {
+    pub fn new(hours: i32, minutes: i32) -> Self {
+        Self {
+            minutes: Self::as_minutes(hours, minutes),
+        }
+    }
+
+    pub fn add_minutes(&self, minutes: i32) -> Self {
+        Self::new(0, self.minutes + minutes)
+    }
+
+    fn as_minutes(hours: i32, minutes: i32) -> i32 {
+        ((hours * MINUTES_IN_AN_HOUR + minutes) % MINUTES_IN_A_DAY + MINUTES_IN_A_DAY)
+            % MINUTES_IN_A_DAY
+    }
+
+    fn hours(&self) -> i32 {
+        self.minutes / MINUTES_IN_AN_HOUR
+    }
+
+    fn minutes(&self) -> i32 {
+        self.minutes % MINUTES_IN_AN_HOUR
+    }
+}