Best way to get whole number part of a Decimal num

Question

What is the best way to return the whole number part of a decimal (in c#)? (This has to work for very large numbers that may not fit into an int).

GetIntPart(343564564.4342) >> 343564564
GetIntPart(-323489.32) >> -323489
GetIntPart(324) >> 324

The purpose of this is: I am inserting into a decimal (30,4) field in the db, and want to ensure that I do not try to insert a number than is too long for the field. Determining the length of the whole number part of the decimal is part of this operation.

Answer 1

Depends on what you're doing.

For instance:

//bankers' rounding - midpoint goes to nearest even
GetIntPart(2.5) >> 2
GetIntPart(5.5) >> 6
GetIntPart(-6.5) >> -6

or

//arithmetic rounding - midpoint goes away from zero
GetIntPart(2.5) >> 3
GetIntPart(5.5) >> 6
GetIntPart(-6.5) >> -7

The default is always the former, which can be a surprise but makes very good sense.

Your explicit cast will do:

int intPart = (int)343564564.5
// intPart will be 343564564

int intPart = (int)343564565.5
// intPart will be 343564566

From the way you've worded the question it sounds like this isn't what you want - you want to floor it every time.

I would do:

Math.Floor(Math.Abs(number));

Also check the size of your decimal - they can be quite big, so you may need to use a long.