Answer by Patrick Oniel Bernardo for Difference in months between two dates

public partial class Form1 : Form{    public Form1()    {        InitializeComponent();    }    private void button1_Click(object sender, EventArgs e)    {        label3.Text = new DateDifference(Convert.ToDateTime("2018-09-13"), Convert.ToDateTime("2018-11-15")).ToString();        label2.Text = new DateDifference(Convert.ToDateTime("2018-10-12"), Convert.ToDateTime("2018-11-15")).ToString();        DateDifference oDateDifference = new DateDifference(Convert.ToDateTime("2018-11-12"));       label1.Text  =   oDateDifference.ToString();    }}public class DateDifference{    public DateTime start { get; set; }    public DateTime currentDAte { get; set; }    public DateTime origstart { get; set; }    public DateTime origCurrentDAte { get; set; }    int days { get; set; }    int months { get; set; }    int years { get; set; }    public DateDifference(DateTime postedDate, DateTime currentDAte)    {        this.start = this.removeTime(postedDate);        this.currentDAte = this.removeTime(currentDAte);        this.origstart = postedDate;        this.origCurrentDAte = currentDAte;    }    public DateDifference(DateTime postedDate)    {        DateTime currentDate_ = DateTime.Now;        this.start = this.removeTime(postedDate);        this.currentDAte = this.removeTime(currentDate_);        this.origstart = postedDate;        this.origCurrentDAte = currentDate_;        if (start > this.currentDAte)        {            throw new Exception("Current date is greater than date posted");        }        this.compute();    }    void compute()    {        while (this.start.Year <= this.currentDAte.Year)        {            if (this.start.Year <= this.currentDAte.Year && (this.start.AddMonths(1) <= this.currentDAte))            {++this.months;                this.start = this.start.AddMonths(1);            }            if ((this.start.Year == this.currentDAte.Year) && (this.start >= this.currentDAte.AddMonths(-1) && this.start <= this.currentDAte))            {                break;            }        }        while (this.start.DayOfYear < this.currentDAte.DayOfYear)        {++this.days;            this.start = start.AddDays(1);        }        if (this.months > 11)        {            while (this.months > 11)            {++this.years;                this.months = months - 12;            }        }    }    public override string ToString()    {        if (this.start > this.currentDAte)        {            throw new Exception("Current date is greater than date posted");        }        String ret = this.ComposeTostring();        this.reset();        return ret;    }    private String ComposeTostring()    {        this.compute();        if (this.years > 0)        {            if (this.months > 0)            {                if (this.days > 0)                {                    return String.Format("{0} year{1}, {2} month{3} && {4} Day{5} ago", this.years, plural(this.years), this.months, plural(this.months), this.days, plural(this.days));                }                return String.Format("{0} year{1}, {2} month{3} ago", this.years, plural(this.years), this.months, plural(this.months));            }            else            {                if (this.days > 0)                {                    return String.Format("{0} year{1},{2} day{3} ago", this.years, plural(this.years), this.days, plural(this.days));                }                return String.Format("{0} year{1} ago", this.years, plural(this.years));            }        }        if (this.months > 0)        {            if (this.days > 0)            {                return String.Format("{0} month{1}, {2} day{3} ago", this.months, plural(this.months), this.days, plural(this.days));            }            else            {                return String.Format("{0} month{1} ago", this.months, plural(this.months));            }        }        if ((this.origCurrentDAte - this.origstart).Days > 0)        {            int daysDiff = (this.origCurrentDAte - this.origstart).Days;            this.origstart = this.origstart.AddDays(daysDiff);            int HoursDiff = (this.origCurrentDAte - this.origstart).Hours;            return String.Format("{0} day{1}, {2} hour{3} ago", daysDiff, plural(daysDiff), HoursDiff, plural(HoursDiff));        }        else if ((this.origCurrentDAte - this.origstart).Hours > 0)        {            int HoursDiff = (this.origCurrentDAte - this.origstart).Hours;            this.origstart = this.origstart.AddHours(HoursDiff);            int MinDiff = (this.origCurrentDAte - this.origstart).Minutes;            return String.Format("{0} hour{1}, {2} minute{3} ago", HoursDiff, plural(HoursDiff), MinDiff, plural(MinDiff));        }        else if ((this.origCurrentDAte - this.origstart).Minutes > 0)        {            int MinDiff = (this.origCurrentDAte - this.origstart).Minutes;            this.origstart = this.origstart.AddMinutes(MinDiff);            int SecDiff = (this.origCurrentDAte - this.origstart).Seconds;            return String.Format("{0} minute{1}, {2} second{3} ago", MinDiff, plural(MinDiff), SecDiff, plural(SecDiff));        }        else if ((this.origCurrentDAte - this.origstart).Seconds > 0)        {            int sec = (this.origCurrentDAte - this.origstart).Seconds;            return String.Format("{0} second{1}", sec, plural(sec));        }        return "";    }    String plural(int val)    {        return (val > 1 ? "s" : String.Empty);    }    DateTime removeTime(DateTime dtime)    {        dtime = dtime.AddHours(-dtime.Hour);        dtime = dtime.AddMinutes(-dtime.Minute);        dtime = dtime.AddSeconds(-dtime.Second);        return dtime;    }    public void reset()    {        this.days = 0;        this.months = 0;        this.years = 0;        this.start = DateTime.MinValue;        this.currentDAte = DateTime.MinValue;        this.origstart = DateTime.MinValue;        this.origCurrentDAte = DateTime.MinValue;    }}