Ternary operator expression

Hi,

How this expression will be evaluated??? help me out

Code:

---

((a>b)?((a>c)?a:c):((b>c)?b:c))

---

Quote:

---

Originally Posted by rits

How this expression will be evaluated?

---

Quickly.

If you want to know what the expression does, analyse it yourself following what you know of the ternary operator.

the ?: operator is directly related to if..else statements. convert one to the other and you know how it works.

Code:

---

// ((a>b)?((a>c)?a:c):((b>c)?b:c))
if (a > b)
{
    if (a > c)
        a;
    else
        c;
}
else
{
    if (b > c)
        b;
    else
        c;
}

---

Thanks Meldreth very clear explanation... :)

It's worth noting that the ternary operator evaluates to a value, unlike if-else statements; so, for example, you can do something like this . . .

Code:

---

sign = (number < 0 ? -1 : 1);

---

Then sign is assigned the value -1 if number is negative, and +1 otherwise.

According to my limited thinking thats also if-else. if number is less than 0 sign is -1 otherwise 1

Quote:

---

Originally Posted by rits

According to my limited thinking thats also if-else. if number is less than 0 sign is -1 otherwise 1

---

Yes, what dwks was trying to say is that the use of the ternary operator is slightly different from an if (although it has the same effect).
You can not do:

Code:

---

x = if(a < b) a; else b;

---

That will not compile.
You could do:

Code:

---

if (a < b) x = a; else x = b;

---

or you can use the ternary form:

Code:

---

x = (a < b)?a:b;

---

The latter comes in very handy if you have a long expression:
If-statements:

Code:

---

if (a < b)
    x = 3.6 * y + 9.6 *b;
else
    x = 3.6 * y + 9.6 * a;

---

would be a bit easier on the hands typing and the eyes reading it like this:

Code:

---

  x = 3.6 *y + 9.6 * (a < b)?b:a;

---

Note that there are situations when this is RIGHT, and other times when it is wrong. It may be better to have a temporary variable:

Code:

---

double bigger = a;
if (a < b)
    bigger = b;
x = 3.6 * y + 9.6 * bigger;

---

--
Mats

The conditional evaluation is a compact way of expressing an if-else.

As I tried to say, the conditional operator is pretty much the same thing as an if-else statement. However, the ternary operator evaluates to a value, whereas an if-else construct does not. Whether you use this value is up to you.

You can always convert a ternary operator into an if-else, but it's not quite as simple as Meldreth has made out if the value of the expression is used. That's all I was trying to say, and matsp has elaborated nicely where I was too lazy to. :)

Hey buddies thanks to all of you :)