? and :

**Rhodium** · 03-30-2003

could someone tell me what each part of the following line does?

Code:

compare= (sort_type) ? reverse : alpha;

Thanx

**Stoned_Coder** · 03-30-2003

Code:

if (sort_type)
   compare = reverse;
else
   compare = alpha;

( condition ) ? true:false

**stumon** · 03-30-2003

This says If the first statement is true, do the second part, otherwise, do the 3rd part.

Code:

(if this is true) ? (do this) : (if not, do this);

-edit- You beat me by less than a minute. ;D

**Xei** · 03-30-2003

I never knew that C/C++ supported syntax like that. Is there any other types like that? I also have another question, is there a way to do something 'similar' to the following using such syntax?

Code:

if(Result != 5)
{
     a++;
     b++;
}
else
{
     C+=2;
     D-=2;
}

Thanks.

**Mister C** · 03-30-2003

Yes, C, C++, Java and C# - all have the conditional operator (?

- the only ternary operator!!

**lchunr** · 03-31-2003

Perhaps you should avoid use of this operator, e.g.

Code:

array_index = (array_size > MAX_array) ? first_array_index : last_array_index;

because you will get difficult to read and understand the programming logic.

There is no way to do the similiar thing using ? : operator.

Code:

if(Result != 5)
{
  a++;
  b++;
}
else
{
  C+=2;
  D-=2;
}

**C-learning** · 03-31-2003

Why not use the comma operator , like this:

Code:

(result!=5) ? (a++,b++) : (C+=2,D-=2);

Should work fine.

**Shiro** · 03-31-2003

>Perhaps you should avoid use of this operator

You should not avoid it, but use it with care. In the first example you gave the use of the operator is done in a very clear way. In the other example, I'd prefer the if-else-construction for readability.

**XSquared** · 03-31-2003

Here's a bubble sort function where conditionals add to the unreadability.

Code:

void bubbleSort(int n[],int s)
{
	int i,j;
	for(i=0;i<s;i++)
		for(j=0;j<s-1;j++)
			n[j]=(n[j+1]<n[j]?n[j]^=(n[j+1]^=(n[j]^=n[j+1])):n[j]);
}

**Brighteyes** · 03-31-2003

Here's a bubble sort function where conditionals add to the unreadability.

And undefinedness. You can't change a variable more than once between sequence points, so

Code:

n[j]=(n[j+1]<n[j]?n[j]^=(n[j+1]^=(n[j]^=n[j+1])):n[j]);

is definitely undefined since parentheses are not a sequence point.

**XSquared** · 03-31-2003

Screw conformity. It works for me.

**Brighteyes** · 03-31-2003

Screw conformity. It works for me.

Remind me never to use any programs that you write.

**quzah** · 03-31-2003

Originally posted by XSquared
Here's a bubble sort function where conditionals add to the unreadability.

That's a pretty poor execuse of why not to use said operator. That's like saying "Here's an example where pointers are used in a poorly illustrated, confusing example. So you should avoid pointers all together."

Quzah.

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