Syntax Question

[pgav]

Looking at this syntax, I can't quite see what the end result should be. What does this function return? long comm_fm_node_id(comm_fm_dev_t *dev, long group) { return (group == 0) ? MCAST_nodeid : -1; } Patrick

[Justin Tay]

if(group == 0) return MCAST_nodeid; else return -1;

[toxcct]

it means :

long comm_fm_node_id(comm_fm_dev_t *dev, long group) {
if (group == 0) {
return MCAST_nodeid;
}
else {
return -1;
}
}

but i really don't see what dev is passed to the function if it doesn't use it, and i suspect MCAST_nodeid to be a global variable...

---

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[pgav]

Dev isn't used because it's only a partial implementation... I'm trying to finish the implementation... :) Thanks for your help. Patrick

[Zac Howland]

pgav wrote:

long comm_fm_node_id(comm_fm_dev_t *dev, long group) { return (group == 0) ? MCAST_nodeid : -1; }

By the way, be VERY judicious when using the ternary operator (which is what the expression ? result_if_true : result_if_false is called). Most of the time, it is far more clear to write:

if (expression)
{
	return SomeValue;
}
else
{
	return SomeOtherValue;
}

I can't tell you how many bugs I've run into because people tried to get fancy with the ternary operator and do things like:

return expression1 ? expression2 ? expression4 ? 1 : 0 : 3 : expression3 ? 2 : 4;

If you run into something like that, you should hunt down the person who wrote it, take them out behind your office, and ... well, you get the idea. If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week Zac