Knowledge Base

PRB: "Overflow" with Integer Division and MOD Operator

Article ID: 205053

Article Last Modified on 6/28/2004

APPLIES TO

This article was previously published under Q205053

SYMPTOMS

When using a number larger than 2,147,483,647 (or smaller than -2,147,483,648) with the Mod operator or the integer division operator (\), you receive the following error message:
Run Time Error '6':
Overflow

CAUSE

The Visual Basic Help topic for the Mod operator and the integer division operator (\) explains that if floating point numbers are used in the expression, they are converted to Longs first. Thus, if the floating point number is greater than the maximum value of a Long (2,147,483,647), or less than the minimum value for a long (-2,147,483,648), an overflow error will occur.

RESOLUTION

The following code demonstrates how to perform integer division and modulo arithmetic when the size of an operand is sufficiently large to cause overflow: 
Dim dblX as Double
Dim dblY as Double
dblX = 2147483648                ' numerator
dblY = 123                       ' denominator

' round off the numerator and denominator (ensure number is .0)
dblX = INT(dblX + .5)         
dblY = INT(dblY + .5)      

' Emulate integer division
MsgBox FIX(dblX / dblY)             
' Emulate modulo arithmetic
MsgBox dblX - ( dblY * FIX(dblX / dblY) )

STATUS

This behavior is by design.

Keywords: kberrmsg kbprb KB205053


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