negative to positive

Hi,

This is a really easy question I'm sure but I can't figure it out in a simple way.

Let's say I have A + B = C

and A is 100 and B is -200 so C = -100

How can I get C as a positive number?

I need this for a rectangle drawing function I'm writing where the mouse down and mouse up coordinates can be positive or negative.

What I'm really looking for is the difference between A and B as a positive number.

Any help?

Thanks

T

x - y is the same as x + (-y) so in your case wouldnt you get a negative value either way? if this is supposed to be coded why don't you just use C's absolute value?

I'm guessing that as it is rectangles all lines are horizontal or vertical, in which case Something Else's code is a little over the top (but required if lines are at an angle) . In VB you can do this:

C = Abs(A + B)

If not in VB, then do this:
if C < 0 then
C= 0-C
end if

There's an absolute function in nearly every language.
Mathematical notation is
|a|

You could also multiply by -1

C = 0 - C
or
C = -C
is probably faster than
C = C * -1

And if its in C, you could do
C *=-1;

still slower.

C *=-1;

is the same as C = C * (-1)

but C = 0-C is definitely faster(a littttttttttttttttttttttle)