关于Hoursbetween函数

[zhourongbiao]

下面的代码应该输出1吧?可是输出了0！
help里说
HoursBetween reports the difference between 9:00 AM and 9:59:59 AM as 0 because the difference is one second short of an entire hour.
可是好像只对起始时间非0的有效。

uses DateUtils;

procedure TForm1.Button1Click(Sender: TObject);
var
dtStart, dtEnd : TDateTime;
nowDate, LastDate : TDate;
ftMax, ftMin : double;
begin
dtStart := IncHour( DateOf(now), StrToInt('0') );
dtEnd := IncHour( DateOf(now), StrToInt('1') );
ShowMessage( IntToStr(Hoursbetween(dtStart,dtEnd) ))
end;

[qi7]

Thus, HoursBetween reports the difference between 9:00 AM and 9:59:59 AM as 0 because the difference is one second short of an entire hour.

[僵哥]

关键问题出在Trunc与浮点数。

[xixuemao]

ShowMessage( IntToStr(Hoursbetween(strtodatetime('2005-7-22 9:00:00'),strtodatetime('2005-7-22 9:59:59'))))

如果这样就可以返回1。晕了！

[xixuemao]

procedure TForm1.Button1Click(Sender: TObject);
var
dtStart, dtEnd : TDateTime;
begin
dtStart := now;//IncHour( now, StrToInt('0') );
dtEnd := now+strtotime('2:00:00');//IncHour( now, StrToInt('1') );
showmessage(datetimetostr(dtstart));
showmessage(datetimetostr(dtend));

ShowMessage( IntToStr(Hoursbetween(dtStart,dtEnd)))
end;

你再试试这个，返回2，又对了，我更晕。差一天返回24也对了，就差1小时返回的值不对。

[xixuemao]

唉，终于测试出来了，必须超过1小时才返回1呢，正好＝1小时返回0；
procedure TForm1.Button1Click(Sender: TObject);
var
dtStart, dtEnd : TDateTime;
begin
dtStart := now;//IncHour( now, StrToInt('0') );
dtEnd := now+strtotime('1:00:01');//IncHour( now, StrToInt('1') );
showmessage(datetimetostr(dtstart));
showmessage(datetimetostr(dtend));

ShowMessage( IntToStr(Hoursbetween(dtStart,dtEnd)))
end;

[bxh2dai]

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