right associativity and order of execution of nested ternary operator in c-CodePudding

I have the solution regarding execution order, but I cant understand how right associativity is linked to SCENARIO 2.

a ? b: c ? d : e ? f : g ? h : i // scenario 1 : associativity understood, which is : (a?b:(c?d:(e?f:(g?h:i))))

and

a ? b ? c : d : e // scenario 2 : NOT UNDERSTOOD

From the first answer here, I am able to understand the first scenario but not the second.

CodePudding user response：

The obvious (and generally best) advice about things like this is "just don't do it."

Other than that, I find the easiest approach to be to think of them like Algol-style ifs. An Algol if was an expression, not a statement, so (much like a conditional, except readable) you could write something like this:

a = if b then c else d;

The transformation is really pretty simple. x ? is if (x) and : is else. Applying this to a nested conditional is actually pretty easy, and at least in my opinion, the result is much more readable.

a ? b: c ? d : e ? f : g ? h : i

Transforms to:

if (a) {
    b; 
} else if (c) {
    d; 
} else if (e) {
    f;
} else if (g) {
    h;
} else {
    i;
}

The second is actually just about as easy, as long as you remember that x ? translates directly to if (x). Other than that, we follow the normal C rule that an else matches up with the most recent if that doesn't already have an else associated with it.

a ? b ? c : d : e

...becomes:

if (a) {
    if (b) {
        c;
    }
    else {
        d;
    }
} else {
    e;
};