实现一个处理没有日期的时间的 clock.

您应该可以添加和减去,分钟数.

代表相同时间的两个时钟应该彼此相等.

你为 Clock 结构实现了.to_string()吗?

如果是这样,请尝试为 Clock 实现Display trait(特征)

特征为各种类型的功能实现，提供了通用方法.

对于其他学习, 可以试试为 Clock 类型实现 String::from?

与 Erin Drummond 的配对会议https://twitter.com/ebdrummond

pub struct Clock;

impl Clock {
   pub fn new(hours: i32, minutes: i32) -> Self {
       unimplemented!(
           "Construct a new Clock from {} hours and {} minutes",
           hours,
           minutes
       );
   }

   pub fn add_minutes(self, minutes: i32) -> Self {
       unimplemented!("Add {} minutes to existing Clock time", minutes);
   }
}

# #![allow(unused_variables)]
#fn main() {
//
// Clock Creation
//

#[test]
fn test_on_the_hour() {
   assert_eq!(Clock::new(8, 0).to_string(), "08:00");
}

#[test]
//#[ignore]
fn test_past_the_hour() {
   assert_eq!(Clock::new(11, 9).to_string(), "11:09");
}

#[test]
//#[ignore]
fn test_midnight_is_zero_hours() {
   assert_eq!(Clock::new(24, 0).to_string(), "00:00");
}

#[test]
//#[ignore]
fn test_hour_rolls_over() {
   assert_eq!(Clock::new(25, 0).to_string(), "01:00");
}

#[test]
//#[ignore]
fn test_hour_rolls_over_continuously() {
   assert_eq!(Clock::new(100, 0).to_string(), "04:00");
}

#[test]
//#[ignore]
fn test_sixty_minutes_is_next_hour() {
   assert_eq!(Clock::new(1, 60).to_string(), "02:00");
}

#[test]
//#[ignore]
fn test_minutes_roll_over() {
   assert_eq!(Clock::new(0, 160).to_string(), "02:40");
}

#[test]
//#[ignore]
fn test_minutes_roll_over_continuously() {
   assert_eq!(Clock::new(0, 1723).to_string(), "04:43");
}

#[test]
//#[ignore]
fn test_hours_and_minutes_roll_over() {
   assert_eq!(Clock::new(25, 160).to_string(), "03:40");
}

#[test]
//#[ignore]
fn test_hours_and_minutes_roll_over_continuously() {
   assert_eq!(Clock::new(201, 3001).to_string(), "11:01");
}

#[test]
//#[ignore]
fn test_hours_and_minutes_roll_over_to_exactly_midnight() {
   assert_eq!(Clock::new(72, 8640).to_string(), "00:00");
}

#[test]
//#[ignore]
fn test_negative_hour() {
   assert_eq!(Clock::new(-1, 15).to_string(), "23:15");
}

#[test]
//#[ignore]
fn test_negative_hour_roll_over() {
   assert_eq!(Clock::new(-25, 00).to_string(), "23:00");
}

#[test]
//#[ignore]
fn test_negative_hour_roll_over_continuously() {
   assert_eq!(Clock::new(-91, 00).to_string(), "05:00");
}

#[test]
//#[ignore]
fn test_negative_minutes() {
   assert_eq!(Clock::new(1, -40).to_string(), "00:20");
}

#[test]
//#[ignore]
fn test_negative_minutes_roll_over() {
   assert_eq!(Clock::new(1, -160).to_string(), "22:20");
}

#[test]
//#[ignore]
fn test_negative_minutes_roll_over_continuously() {
   assert_eq!(Clock::new(1, -4820).to_string(), "16:40");
}

#[test]
//#[ignore]
fn test_negative_hour_and_minutes_both_roll_over() {
   assert_eq!(Clock::new(-25, -160).to_string(), "20:20");
}

#[test]
//#[ignore]
fn test_negative_hour_and_minutes_both_roll_over_continuously() {
   assert_eq!(Clock::new(-121, -5810).to_string(), "22:10");
}

//
// Clock Math
//

#[test]
//#[ignore]
fn test_add_minutes() {
   let clock = Clock::new(10, 0).add_minutes(3);
   assert_eq!(clock.to_string(), "10:03");
}

#[test]
//#[ignore]
fn test_add_no_minutes() {
   let clock = Clock::new(6, 41).add_minutes(0);
   assert_eq!(clock.to_string(), "06:41");
}

#[test]
//#[ignore]
fn test_add_to_next_hour() {
   let clock = Clock::new(0, 45).add_minutes(40);
   assert_eq!(clock.to_string(), "01:25");
}

#[test]
//#[ignore]
fn test_add_more_than_one_hour() {
   let clock = Clock::new(10, 0).add_minutes(61);
   assert_eq!(clock.to_string(), "11:01");
}

#[test]
//#[ignore]
fn test_add_more_than_two_hours_with_carry() {
   let clock = Clock::new(0, 45).add_minutes(160);
   assert_eq!(clock.to_string(), "03:25");
}

#[test]
//#[ignore]
fn test_add_across_midnight() {
   let clock = Clock::new(23, 59).add_minutes(2);
   assert_eq!(clock.to_string(), "00:01");
}

#[test]
//#[ignore]
fn test_add_more_than_one_day() {
   let clock = Clock::new(5, 32).add_minutes(1500);
   assert_eq!(clock.to_string(), "06:32");
}

#[test]
//#[ignore]
fn test_add_more_than_two_days() {
   let clock = Clock::new(1, 1).add_minutes(3500);
   assert_eq!(clock.to_string(), "11:21");
}

#[test]
//#[ignore]
fn test_subtract_minutes() {
   let clock = Clock::new(10, 3).add_minutes(-3);
   assert_eq!(clock.to_string(), "10:00");
}

#[test]
//#[ignore]
fn test_subtract_to_previous_hour() {
   let clock = Clock::new(10, 3).add_minutes(-30);
   assert_eq!(clock.to_string(), "09:33");
}

#[test]
//#[ignore]
fn test_subtract_more_than_an_hour() {
   let clock = Clock::new(10, 3).add_minutes(-70);
   assert_eq!(clock.to_string(), "08:53");
}

#[test]
//#[ignore]
fn test_subtract_across_midnight() {
   let clock = Clock::new(0, 3).add_minutes(-4);
   assert_eq!(clock.to_string(), "23:59");
}

#[test]
//#[ignore]
fn test_subtract_more_than_two_hours() {
   let clock = Clock::new(0, 0).add_minutes(-160);
   assert_eq!(clock.to_string(), "21:20");
}

#[test]
//#[ignore]
fn test_subtract_more_than_two_hours_with_borrow() {
   let clock = Clock::new(6, 15).add_minutes(-160);
   assert_eq!(clock.to_string(), "03:35");
}

#[test]
//#[ignore]
fn test_subtract_more_than_one_day() {
   let clock = Clock::new(5, 32).add_minutes(-1500);
   assert_eq!(clock.to_string(), "04:32");
}

#[test]
//#[ignore]
fn test_subtract_mores_than_two_days() {
   let clock = Clock::new(2, 20).add_minutes(-3000);
   assert_eq!(clock.to_string(), "00:20");
}

//
// Test Equality
//

#[test]
//#[ignore]
fn test_compare_clocks_for_equality() {
   assert_eq!(Clock::new(15, 37), Clock::new(15, 37));
}

#[test]
//#[ignore]
fn test_compare_clocks_a_minute_apart() {
   assert_ne!(Clock::new(15, 36), Clock::new(15, 37));
}

#[test]
//#[ignore]
fn test_compare_clocks_an_hour_apart() {
   assert_ne!(Clock::new(14, 37), Clock::new(15, 37));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_hour_overflow() {
   assert_eq!(Clock::new(10, 37), Clock::new(34, 37));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_hour_overflow_by_several_days() {
   assert_eq!(Clock::new(3, 11), Clock::new(99, 11));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_hour() {
   assert_eq!(Clock::new(22, 40), Clock::new(-2, 40));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_hour_that_wraps() {
   assert_eq!(Clock::new(17, 3), Clock::new(-31, 3));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_hour_that_wraps_multiple_times() {
   assert_eq!(Clock::new(13, 49), Clock::new(-83, 49));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_minutes_overflow() {
   assert_eq!(Clock::new(0, 1), Clock::new(0, 1441));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_minutes_overflow_by_several_days() {
   assert_eq!(Clock::new(2, 2), Clock::new(2, 4322));
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_minute() {
   assert_eq!(Clock::new(2, 40), Clock::new(3, -20))
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_minute_that_wraps() {
   assert_eq!(Clock::new(4, 10), Clock::new(5, -1490))
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_minute_that_wraps_multiple() {
   assert_eq!(Clock::new(6, 15), Clock::new(6, -4305))
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_hours_and_minutes() {
   assert_eq!(Clock::new(7, 32), Clock::new(-12, -268))
}

#[test]
//#[ignore]
fn test_compare_clocks_with_negative_hours_and_minutes_that_wrap() {
   assert_eq!(Clock::new(18, 7), Clock::new(-54, -11513))
}

#[test]
//#[ignore]
fn test_compare_full_clock_and_zeroed_clock() {
   assert_eq!(Clock::new(24, 0), Clock::new(0, 0))
}

#}

# #![allow(unused_variables)]
#fn main() {
use std::fmt;

#[derive(Eq, PartialEq, Debug)]
pub struct Clock {
   minutes: i32,
}

impl fmt::Display for Clock {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
       let hours = self.minutes / 60;
       let mins = self.minutes % 60;
       write!(f, "{:02}:{:02}", hours, mins)
   }
}

impl Clock {
   pub fn new(hour: i32, minute: i32) -> Self {
       Clock::build(hour * 60 + minute)
   }

   fn build(minutes: i32) -> Self {
       let mut mins = minutes;
       while mins < 0 {
           mins += 1440;
       }
       Clock {
           minutes: mins % 1440,
       }
   }

   pub fn add_minutes(&mut self, minutes: i32) -> Self {
       Clock::build(self.minutes + minutes)
   }
}

#}