What does val = val==0?0:1; mean?

Question

Normally, I usually see i++; or ++i;. However, this is my first time to see something like this:

val = val == 0 ? 0 : 1;

What does it mean?

@bhspencer It depends. If the variables and methods are properly named and the line is short and understandable, it is a good choice. — Edu, Apr 15 '18 at 17:41
In addition to the already correct answers, I find it as being overkill to do `val = val == 0 ? 0 : 1;` , instead simply do `if(val != 0) val = 1;` — Ousmane D., Apr 15 '18 at 17:46

score 3 · Answer 1 · answered Apr 15 '18 at 17:34

3

The code val = val==0?0:1; is a shorter representation of this code:

if (val==0)
{
    val = 0;
}
else
{
    val = 1;
}

The syntax of a?b:c is:

<condition> ? <result if true> : <result if false>

answered Apr 15 '18 at 17:34

Edu

score 2 · Answer 2 · edited Apr 15 '18 at 17:49

2

It means if val == 0 then set val to 0 else set val to 1

edited Apr 15 '18 at 17:49

Sam

answered Apr 15 '18 at 17:35

DCR

please only format code as code – Neuron Apr 15 '18 at 17:49
I just typed it in, the site added `` when it saw the if -> talk to SO if you don't like the formatting – DCR Apr 15 '18 at 18:12
No need to get grumpy – Neuron Apr 15 '18 at 18:17

score 2 · Answer 3 · answered Apr 15 '18 at 17:35

2

It is using the ternary conditional operator, which looks like

condition ? [value if true] : [value if false].

In this case, it is saying that if val == 0, then set val to 0; otherwise, set val to 1.

Hope this helps!

answered Apr 15 '18 at 17:35

Sam

score 2 · Answer 4 · answered Apr 15 '18 at 17:36

2

This is the so-called ternary operator, which can be viewed as an "immediate if" expression, that is to say:

val = val == 0 ? 0 : 1;

amounts to:

if (val == 0) {
    val = 0;
} else {
    val = 1;
}

answered Apr 15 '18 at 17:36

ErikMD

4 Answers4