IF statement in Formula Node

[Tom_SAVU]

I have the following statement in a Formula Node in LabVEW 7.1:

if (x=1) y = 3; else y = 1;

When running the VI, whatever the value of X is, I obtain Y = 3 !!!!

Why ???

Tom

[becktho]

Try x == 1 (instead of x = 1).

[Rod42]

The formula node uses c-like constructs, so if you want to check for equality use " if (x==1) ..... "

With a single = sign in the 'test' it becomes an assignment. In C the expression (x=1) has the value of the right hand side of the assignment, here 1 (true) so the true part of the if will always execute. It's a common source of error in c programming.

I presume that this is part of a larger formula, ortherwise you should use native LabVIEW tests.

Rod.

[Tom_SAVU]

Thanks Becktho, thanks Rod !