## Binary Subtraction

Continuing our look at maths functions in binary (hex is to come) lets have a quick look at subtraction

 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 function Get-BinaryDifference { param(     [string]\$value1,     [string]\$value2 ) ## check valid binary numbers ## move this to a validation test     Test-Binary \$value1     Test-Binary \$value2     \$diff = (ConvertTo-Decimal -inputvalue \$value1 -binary) -`      (ConvertTo-Decimal -inputvalue \$value2 -binary)     if (\$diff -lt 0){Throw "Binary subtraction produces negative number"}     else {ConvertTo-Binary -inputvalue \$diff} }

Always assume that value2 will be subtracted from value1 therefore value2 should be smaller.

The function is the same as the addition except we perform a subtraction ðŸ™‚

And we check to see if we have a negative result.  If so throw a wobbly and end the action.

These binary and hex functions will be the next module added to PSAM on codeplex

#### 2 Responses to Binary Subtraction

• ALEXAQ says:

1000111011101110111011 CONVERT TO DECIMAL !!!

• RichardSiddaway says:

I tried
ConvertTo-Decimal -inputvalue 1000111011101110111011 -binary

and got 2341819 which is the same answer I got using the Windows calculator

I don’t understand the comment