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MinutesBetween() returns varying values.

Posted on 2002-05-12
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Last Modified: 2012-06-21
Why do the following two calls to MinutesBetween return two different values?  I've tried substituting equivalent TDateTime values in place of the StrToTime calls, with the same result.

MinutesBetween(StrToTime('12:00'), StrToTime('13:00')) = 59.

MinutesBetween(StrToTime('13:00'), StrToTime('14:00')) = 60.

Brian
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Question by:Traal
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Expert Comment

by:MBo
ID: 7005219
What is MinutesBetween function?
TDateTime is float type, so rounding isn't absolutely exact. I suppose MinutesBetween looks like:

Result:=Trunc(Abs(Time1-Time2)/1440);

you may modify it

Result:=Trunc(0.000001+Abs(Time1-Time2)/1440);
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Author Comment

by:Traal
ID: 7005231
It's in DateUtils, and looks like this:

function MinutesBetween(const ANow, AThen: TDateTime): Int64;
begin
  Result := Trunc(MinuteSpan(ANow, AThen));
end;


function MinuteSpan(const ANow, AThen: TDateTime): Double;
begin
  Result := MinsPerDay * SpanOfNowAndThen(ANow, AThen);
end;


function SpanOfNowAndThen(const ANow, AThen: TDateTime): TDateTime;
begin
  if ANow < AThen then
    Result := AThen - ANow
  else
    Result := ANow - AThen;
end;

Brian
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Accepted Solution

by:
MBo earned 50 total points
ID: 7005613
Oh, my mistake- I've written /1440 instead of *1440
Make this function
function MinutesBetweenEx(const ANow, AThen: TDateTime): Int64;  // Integer is enough
begin
Result:=Trunc(0.000001+Abs(Time1-Time2)*1440);
end;
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Expert Comment

by:pnh73
ID: 9005739
No comment has been added lately, so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area that this question is:

Accept answer from MBo

Please leave any comments here within the next seven days.
 
PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!
 
Paul (pnh73)
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Expert Comment

by:pnh73
ID: 9017626
Thankyou for your response.

Paul (pnh73)
EE Cleanup Volunteer
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