[BUG] or maybe not

[Pendrush]

Dim a As Int : a = 1
Dim b As Int : b = 1
Dim c As Int : c = 1

Do While a = b AND a = c AND b = c
   b = Rnd(1,4)
   c = Rnd(1,4)
Loop
Log(a & "-" & b & "-" & c)

and im getting these results

1-2-2
1-1-2
1-1-3
1-3-2
1-1-2
1-1-3
1-1-3
1-3-2
1-2-3
1-3-1
1-2-2

but when using Do Until and change line to

Do Until a <> b AND a <> c AND b <> c

im getting expected results a, b, c are not same with each other.

 

[thedesolatesoul]

It is not a bug.
This is what your condition states:

Do While a = b AND a = c AND b = c

This is not equivalent to a<>b<>c

If you want all three to be different then use:

Do While a = b OR a = c OR b = c

So if any one of them are similar it keeps generating new numbers.

 

[agraham]

Elementary Boolean transformation

Do While a = b AND a = c AND b = c

becomes

Do Until a <> b OR a <> c OR b <> c

 

[Erel]

There is no bug.

Lets assume that a = 1, b = 1 and c = 2.
The conditions:
1. a = b AND a = c AND b = c => Result is FALSE (because b is not equal to c)
2. a <> b AND a <> c AND b <> c => Result is FALSE (because a equals to b)

So the Do While <condition 1> will exit and the Do Until <condition 2> will not exit.

You can read about boolean algebra here: De Morgan's laws - Wikipedia, the free encyclopedia

 

[Erel]

Triple post. New record

 

[Pendrush]

Thank you, my bad :BangHead:

 

[thedesolatesoul]

Wow, this must be the fastest posting thread!

 

[Pendrush]

Explained under 2 minutes