using System;

using Microsoft.VisualStudio.TestTools.UnitTesting;

​

public class Program

{

    public static string GetTimeInWords(DateTime time)

    {

        // break apart time into hours and minutes

        int hour = Convert.ToInt32(time.ToString("hh"));

        int nextHour = (hour%12)+1;

        int min = time.Minute;

        string result = string.Empty;

        // no minutes, o'clock case

        if (min == 0) {

            result = string.Format("{0} o'clock", hour);

        } else if (min == 1) {

            result = string.Format("{0} minute past {1}", min, hour);

        } else if (min == 30) {

            result = string.Format("half past {0}", hour);

        } else if (min == 15) {

            result = string.Format("quarter past {0}", hour);

        } else if (min < 30) {

            // before the half hour use 'past'

            result = string.Format("{0} minutes past {1}", min, hour);

        } else if (min == 45) {

            // before the half hour use 'past'

            result = string.Format("quarter to {0}", nextHour);

        } else if (min == 59) {

            result = string.Format("{0} minute to {1}", 60-min, nextHour);

        } else  {

            // before the half hour use 'past'

            result = string.Format("{0} minutes to {1}", 60-min, nextHour);

        }

        return result;

    }

    /*

    Borrowed from HackerRank.com

    GetTimeInWords

    Given the time as a DateTime value we may convert it into words, as shown below:

    5:00 -> 5 o'clock

    5:01 -> 1 minute past 5

    5:10 -> 10 minutes past 5

    5:15 -> quarter past 5

    5:30 -> half past 5

    5:40 -> 20 minutes to 6

    5:45 -> quarter to 6

    5:47 -> 13 minutes to 6

    5:28 -> 28 minutes past 5

    At `minutes = 0`, use "o'clock". For `1 <= minutes <= 30`, use "past", and for `30 < minutes` use "to". The output string should use

    12-hour time (i.e., 5:00 am and 5:00 pm both produce "five o'clock")

    */  

    public static void Main()

    {

        Assert.AreEqual("3 o'clock",         GetTimeInWords(DateTime.Parse("3:00 am")));

        Assert.AreEqual("13 minutes to 6",   GetTimeInWords(DateTime.Parse("5:47 pm")));

        Assert.AreEqual("half past 12",      GetTimeInWords(DateTime.Parse("12:30 am")));

        Assert.AreEqual("quarter to 1",      GetTimeInWords(DateTime.Parse("12:45 am")));

        Assert.AreEqual("quarter past 1",    GetTimeInWords(DateTime.Parse("1:15 pm")));

        Assert.AreEqual("1 minute to 12",    GetTimeInWords(DateTime.Parse("11:59 am")));

        Assert.AreEqual("12 minutes past 4", GetTimeInWords(DateTime.Parse("4:12 am")));

        Assert.AreEqual("quarter to 2",      GetTimeInWords(DateTime.Parse("1:45 pm")));

        Assert.AreEqual("20 minutes to 7",   GetTimeInWords(DateTime.Parse("6:40 am")));

        Console.WriteLine("All tests passed");

    }

}