To ternary or not to ternary? [closed]

Question

Use it for simple expressions only:

int a = (b > 10) ? c : d;

Don't chain or nest ternary operators as it hard to read and confusing:

int a = b > 10 ? c < 20 ? 50 : 80 : e == 2 ? 4 : 8;

Moreover, when using ternary operator, consider formatting the code in a way that improve readability:

int a = (b > 10) ? some_value                 
                 : another_value;

It makes debugging slightly more difficult since you can not place breakpoints on each of the sub expressions. I use it rarely.

I love them, especially in type-safe languages.

I don't see how this:

int count = (condition) ? 1 : 0;

is any harder than this:

int count;

if (condition)
{
  count = 1;
}
else
{
  count = 0;
}

I'd argue that ternary operators make everything less complex and more neat than the alternative.

Chained I'm fine with - nested, not so much.

I tend to use them more in C simply because they're an if statement that has value, so it cuts down on unnecessary repetition or variables:

x = (y < 100) ? "dog" :
    (y < 150) ? "cat" :
    (y < 300) ? "bar" : "baz";

rather than

     if (y < 100) { x = "dog"; }
else if (y < 150) { x = "cat"; }
else if (y < 300) { x = "bar"; }
else              { x = "baz"; }

In assignments like this, I find it's less to refactor, and clearer.

When I'm working in ruby on the other hand, I'm more likely to use if...else...end because it's an expression too.

x =   if (y < 100) then "dog"
    elif (y < 150) then "cat"
    elif (y < 300) then "bar"
    else                "baz"
    end

(Although, admittedly, for something this simple, I might just use the ternary operator anyway.)

The ternary ?: operator is merely a functional equivalent of the procedural if construct. So as long as you are not using nested ?: expressions, the arguments for/against the functional representation of any operation applies here. But nesting ternary operations can result in code that is downright confusing (exercise for the reader: try writing a parser that will handle nested ternary conditionals and you will appreciate their complexity).

But there are plenty of situations where conservative use of the ?: operator can result in code that is actually easier to read than otherwise. For example:

int compareTo(Object object) {
    if((isLessThan(object) && reverseOrder) || (isGreaterThan(object) && !reverseOrder)) {
       return 1;
    if((isLessThan(object) && !reverseOrder) || (isGreaterThan(object) && reverseOrder)) {
       return -1;
    else
      return 0;
}

Now compare that with this:

int compareTo(Object object) {
    if(isLessThan(object))
        return reverseOrder ? 1 : -1;
    else(isGreaterThan(object))
        return reverseOrder ? -1 : 1;
    else
       return 0;
}

As the code is more compact, there is less syntactic noise, and by using the ternary operator judiciously (that is only in relation with the reverseOrder property) the end result isn't particularly terse.