Ternary operators, bad practice?

I've heard from a couple of people that using the operators "?:" instead of using "if/else" is bad coding practice and should be avoided unless it makes the code MUCH clearer. Others I have talked to say that everybody uses them. Anyone know which one is true?

I wouldn't say BAD always...

It tends to be less readable at first glance, especially when nested, but it has advantages (namely the fact that it not only executes but returns it's expression)

?: can be used in places where if else cant be used. For instance inside a member initialisation list.

If you think they aren't useful it's just because you haven't tried them. The simplicity and readability can hardly be ignored. I especially like them in return statements.

return ( !bad() && a_ok) ? true : false;

I agree completely. They're really nice for return values. On that note, they're often handy just for general value assignments. It's clean and compact:

Code:

---

if( someTest )
{
    myVar = firstValue;
}
else
{
    myVar = secondValue;
}

myVar = someTest ? firstValue : secondValue;

---

I know which one I prefer in this case. Beyond that, they can be a great deal of fun. :D

return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

Quzah.

Interseting Quzah. I've never used the nested variety. A little unsightly, but interesting. :D

Sometimes you must use ?:

Code:

---

int n;
// do some stuff
printf("You have %d item%s.\n", n, n>1?"s":"");

---

If you use if/else, you will get a long code.
But I found that ?: cant be used with cout, is that right?

Quote:

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Originally posted by Sebastiani

return ( !bad() && a_ok) ? true : false;

---

:confused:
Why do you code like that?
Why not:

Code:

---

return !bad && a_ok;

---

I definately find them useful and use them often within my code. I was just told by a few people that coding standards consider them as unsightly as 'goto' statements, unless they greatly improve readibility. I'm glad that it appears this isn't true :D

Quote:

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Originally posted by Sang-drax
:confused:
Why do you code like that?
Why not:

Code:

---

return !bad && a_ok;

---

---

I know it was a bad example. In practice I would have just used the inherent boolean nature of the comparison...but it was late. :)

>But I found that ?: cant be used with cout, is that right?

nope.. it can be used with cout.

cout<<(isGood()? "it's good" : "it's not so good")<<endl;

every so often you'll need a cast when you're talking about a cout because of course cout::operator << is only overloaded for so many types. But it can definitely be used

Does a ternary operator statement execute faster than a similar if statement?

which would be faster?:

FillYourBrain.alive? GreetFill() : BuryFill();

if(FillYourBrain.alive)
GreetFill();
else
BuryFill();


I don't like the nested ternary operators, if/else seems more appropriate (easier to read)

Quote:

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Originally posted by quzah


return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

---

explain please, lol

Shadow, your example probably compiles exactly the same. Just a guess really but either way I would use the one that felt more readable for that particular instance.

>>return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;
>explain please, lol

if st1 is true, return sv1
else if st2 is true, return sv2
else if st3 is true, return sv3
else return sv4

... i think

nope try again!:D

>>nope try again!

eh? what'd i miss?

Code:

---

int myst(bool st1, bool st2, bool st3)
{
        return st1 ? 1 : st2 ? 2 : st3 ? 3 : 4;
}

int myst2(bool st1, bool st2, bool st3)
{
        if(st1)
                return 1;
        else if(st2)
                return 2;
        else if(st3)
                return 3;
        else
                return 4;
}

---

wrote these (which seem to be the original statement, and my crack at it, unless i missed something), and they return the same thing (given the same values).

return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

if st1 is true then sv1 is passed to next ? operator and if thats true then sv2 is passed to next ? operator and if thats true sv3 is returned if false sv4 is returned.

now what happens when one tests false.

if st1 is false then st2 is passed to next ? op. and if thats false st3 is passed to next ? op and if true sv3 is returned if false sv4 is returned.

whatever the case the only thing that can be returned is sv3 or sv4.

Does the ?: operator have any other name then the ternary operator? We don't call ! the unary operator, nor + the binary operator, so why call ?: the ternary operator?

I think it is know as the ternary conditional operator but everyone knows it as the ternary operator because it is the only one.

hmm... i'm not so sure...

return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

if st1 is true, it places sv1 in the place of all that, so you get

return sv1;

if st1 is false, it places everything right of the : there, so you get

return st2? sv2 : st3 ? sv3 : sv4;

then if st2 is true, it makes that

return sv2;

if st2 is false, it makes it

return st3? sv3 : sv4;

then you either get

return sv3;
or
return sv4;

depending on st3.

i belive this is right, otherwise my function

Code:

---

int myst(bool st1, bool st2, bool st3)
{
        return st1 ? 1 : st2 ? 2 : st3 ? 3 : 4;
}

---

would only return 3 or 4, but it can return 1 or 2 (i tested it).

Quote:

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Originally posted by Stoned_Coder
return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

if st1 is true then sv1 is passed to next ? operator and if thats true then sv2 is passed to next ? operator and if thats true sv3 is returned if false sv4 is returned.

---

That is incorrect. Mad Hatter's first explanation is the correct answer.

Quzah.

Around here we just call them terns.

return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

is this

if (st1)
return sv1? sv2:st3 ? sv3:sv4;
else
return st2? sv2:st3 ? sv3:sv4;

ok so far so good. now lets break this down. first top half
return sv1? sv2:st3 ? sv3:sv4;

if(sv1)
return sv2 ? sv3:sv4;
else
return st3 ? sv3: sv4;

see only sv3 or sv4 can be returned.

now bottom half
return st2? sv2:st3 ? sv3:sv4;
is this

if (st2)
return sv2 ? sv3:sv4;
else
return st3 ? sv3:sv4;

see again only sv3 or sv4 can be returned.

Quzah its your example! u surprise me

Quote:

---

Originally posted by Stoned_Coder
return st1 ? sv1 : st2 ? sv2 : st3 ? sv3 : sv4;

is this

if (st1)
return sv1? sv2:st3 ? sv3:sv4;
else
return st2? sv2:st3 ? sv3:sv4;

---

no, it isn't. it's this

Code:

---

if(st1)
  return sv1;
else
  return st2? sv2 : sv3 ? sv3 : sv4;

---

simply run the function:

Code:

---

int myst(bool st1, bool st2, bool st3)
{
return st1 ? 1 : st2 ? 2 : st3 ? 3 : 4;
}

---

and pass the values (true, true, true) and (false, true, true). you'll see it returns 1 and 2 respectively.

sorry yes you are right. good job i never nest those buggers lol

I never use them, thus destroying any confusion. It could be pretty easy to create hard to find bugs in your code with them.

>It could be pretty easy to create hard to find bugs in your code with them.

if you nest them, yes... but they can be more readable and handier than if/else's at times, IMO.
i would never write code like that which was just discussed.. that was just for fun, i think (and wasn't it just?? ;))

They're not so bad if you add a few parenthesis for readability.

return st1 ? sv1 : (st2 ? sv2 : (st3 ? sv3 : sv4));

it's also called the conditional operator

Quote:

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Originally posted by pianorain
They're not so bad if you add a few parenthesis for readability.

return st1 ? sv1 : (st2 ? sv2 : (st3 ? sv3 : sv4));

---

Depending on the situation, if I need readability, or if the test is lengthy, I usually do something like:

Code:

---

return Condition1 ? ReturnValue1 :
      Condition2 ? ReturnValue2 :
      Condition3 ? ReturnValue3 :
      Condition4 ? ReturnValue4 : Returnvalue5;

---

It makes it farily simple to understand, and its shorter than a big if/else ladder.

Quzah.

I disagree.
Code readability is very important and these codes are equivalent:

Code:

---

return Condition1 ? ReturnValue1 :
      Condition2 ? ReturnValue2 :
      Condition3 ? ReturnValue3 :
      Condition4 ? ReturnValue4 : Returnvalue5;

---

Code:

---

if (Condition1) return ReturnValue1;
if (Condition2) return ReturnValue2;
if (Condition3) return ReturnValue3;
if (Condition4) return ReturnValue4;
return ReturnValue5;

---

The purpose of the code using "if" is (more) obvious, even to a programmer not familiar with C/C++/Java/Omicron. It is easier to read and should therefore be used.

Anyways, I haven't encountered many real-life situations where such return conditions are used.

Quote:

---

Originally posted by quzah

Code:

---

return Condition1 ? ReturnValue1 :
      Condition2 ? ReturnValue2 :
      Condition3 ? ReturnValue3 :
      Condition4 ? ReturnValue4 : Returnvalue5;

---

---

The only time I've done something like that was when I was confusing my second-rate C++ professor. Not saying it's bad...it just has very specialized uses. ;)

>I've heard from a couple of people that using the operators "?:" instead of using "if/else" is bad coding practice and should
>be avoided unless it makes the code MUCH clearer.
It's funny how questions like these seem to crop up so much and turn into large debates. The conditional operator is a Bad Thing like goto is a Bad Thing, it isn't. It's just another tool that if used without discipline can create impenetrable code. Sometimes there's a better solution, sometimes not, but that's a decision up to the individual programmer.

-Prelude