Multiple Logical Operators

[richthomas]

I have been reviewing some extensive backtesting and realised that I may have had an error in my code.

To simplify things I have one part that states (A || B && C) where A, B and C are different conditions that need to be true for a trade to be placed.

I want the test to return true if A is true irrespective of B or C.

If A is false I want the test to return true only if both B and C are true.

I believe I should have coded it with extra brackets as (A || (B && C)).

However I do not want to make the change and rerun the tests (which has taken me days to do) unless I have to.

So based on how I currently have it coded what will the test return if A is false and either of B or C is false?

[ACM]

Re: Multiple Logical Operators

richthomas

So based on how I currently have it coded what will the test return if A is false and either of B or C is false?

That will return false
Alex

Originally posted by richthomas
I have been reviewing some extensive backtesting and realised that I may have had an error in my code.

To simplify things I have one part that states (A || B && C) where A, B and C are different conditions that need to be true for a trade to be placed.

I want the test to return true if A is true irrespective of B or C.

If A is false I want the test to return true only if both B and C are true.

I believe I should have coded it with extra brackets as (A || (B && C)).

However I do not want to make the change and rerun the tests (which has taken me days to do) unless I have to.

So based on how I currently have it coded what will the test return if A is false and either of B or C is false?

[Doji3333]

your last statement is correct. You need

if (A || (B && C)) {

Remember algebra in school??

You need to segment complex math/logic to control order.

Sounds like you need to re-run your tests.

Let me know if you need more help.

[ACM]

richthomas
FWIW your code as is will do what you are expecting (see the screenshots attached to each condition)
Alex

I want the test to return true if A is true irrespective of B or C.

If A is false I want the test to return true only if both B and C are true.

So based on how I currently have it coded what will the test return if A is false and either of B or C is false?

[gspiker]

I believe there is one case that isn't tested in the code Alex did, and would result in incorrect test results:

If A is true and B & C is false, my belief is this will return false. I also believe you would want this to return true in this case.

I haven't tested, but based on the way the logic should be implicitly executed, this should be true.

In general, I would always force any logical operation to be evaluated in the order you want (explicate execution). The same is true of math operations.

Garth

[ACM]

Garth
That case is returning true
Alex

Originally posted by gspiker
I believe there is one case that isn't tested in the code Alex did, and would result in incorrect test results:

If A is true and B & C is false, my belief is this will return false. I also believe you would want this to return true in this case.

I haven't tested, but based on the way the logic should be implicitly executed, this should be true.

In general, I would always force any logical operation to be evaluated in the order you want (explicate execution). The same is true of math operations.

Garth

[gspiker]

I stand corrected (thanks for testing this Alex).

In verifying operator precedence, it does say that && is evaluated before ||. I thought they would have equal precedence and therefore be resolved left to right.

One reason I always do things explicitly is so I don't have to remember this stuff, and in other languages it also makes code portability more reliable.

Garth

[richthomas]

Thanks for all the responses.
I'm glad I don't have to rerun all my tests!
Richard