Finding the difference between two numbers

I

inglewoodpete

Senior Member
From time to time I want to find the difference between two numbers. It doesn't matter which one is smaller or larger, just the difference.

I usually write code like this.
Code: 
[color=Blue]If [/color][color=Purple]w10 [/color][color=DarkCyan]> [/color][color=Purple]w11 [/color][color=Blue]Then
   [/color][color=Purple]w12 [/color][color=DarkCyan]= [/color][color=Purple]w10 [/color][color=DarkCyan]- [/color][color=Purple]w11[/color]
[color=Blue]Else
   [/color][color=Purple]w12 [/color][color=DarkCyan]= [/color][color=Purple]w11 [/color][color=DarkCyan]- [/color][color=Purple]w10   [/color][color=Green]'w12 will equal 0 if w10 & w11 are equal[/color]
[color=Blue]EndIf[/color]
I could write a macro, of course, to hide the cumbersome code but is there a nifty one-line piece of code that I could use instead?
 
hippy

hippy

Technical Support
Staff member
No true one-liner I can think of but this will do the job without an IF ...

Code: 
w12 = w10 Max w11
w12 = w10 Min w11 - w12
MAX and MIN are limiting operations so MAX returns the lowest of two numbers, MIN returns the highest of two numbers.
 
I

inglewoodpete

Senior Member
Thanks hippy, Another gem from your arsenal. Perhaps a "DIF" command could be added to the X3 range, when they arrive ;).

The function is useful when interfacing to the real world where "near enough is close enough".
 
Last edited:
hippy

hippy

Technical Support
Staff member
BillBWann said:
If "close enough" was a difference of 5 or less say, then I’d use the following:-
Click to expand...
Because of the way PICAXE handles numbers, if w10=65535, w11=0, then w10-w11+5 would give a result of 4 which isn't correct.
 
B

BillBWann

Member
hippy said:
Because of the way PICAXE handles numbers, if w10=65535, w11=0, then w10-w11+5 would give a result of 4 which isn't correct.
Click to expand...
I assumed that inglewoodpete was comparing some measured parameter which he was controlling against a given setpoint (say a GPS coordinate of a vehicle against a way point coordinate) and that he would have chosen values for those parameters which wouldn't be in danger of overflowing in his real world situation.
 
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