How/Can you use both && and || in the same if statement condition?

Question

Which logical operator get "prioritized" or "read" ahead of the other, so to say.

For example:

if( x=y || y=y && x=x ){}

is java reading this as: One of these two: (x=y||y=y), AND (x=x)

or as: Either (x=y) or (y=y AND x=x)

Sounds like something that would have been asked or at least easy to find, but alas, "and" + "or" are keywords to Google.

Solution 1

The operator && has a higher precedence than ||, so && will be evaluated first.

http://introcs.cs.princeton.edu/java/11precedence/

Still, many programmers will not remember that fact. It is clearer and more maintenance-friendly to use parenthesis to specifically state the order of evaluation intended.

Note that in your code you write

x=y

that is actually the assignment operator, not the equality operator. Presumably you intend

x==y

Solution 2

x=y || y=y && x=x can work only if both x and y are boolean, since = is assignment, and it is equivalent to y || y && y because you assigned x=y in as in first operation

Comments

[Evan Trimboli]

Any reason you couldn't just test it yourself?

[Jayan]

docs.oracle.com/javase/tutorial/java/nutsandbolts/…

[Krease]

In cases like this, always use brackets for reading clarity

[Krease]

Also be sure to use == instead of just = for your comparisons (is that just a typo in the question?)

[House3272]

@Evan, that's a very good point. What I was working on confuse me to the point of a migraine, not that I fully remember at present.

[ajp15243]

Seconded on using ( ) to separate logical statements. This makes code far easier to read, and makes your meaning transparent.

[Krease]

Dang, you said everything I wanted to say in addition to linking the order of precedence. +1

[House3272]

Thanks! I am aware on both accounts, was just asking. Besides, x==x doesn't make much sense anyhow.