c++ ternary operator...

[sde]

this category is lagging .. so i thought i'd post something cool i learned in c++

the ternary operator ( ? : )

(condition 1) ? (expression 1) : (expression 2 )

so .. if condition 1 is true, then use expression 1 .. else use expression 2

whatFruitToBuy = ( i like apples ) ? buy apples : buy grapes;

anyhow .. just saves some if/else statements.

[redhead]

The constraints how ever, are that the first condition must return in a true or false value.. But since 0 is false and any other value is true, theres not that much constraining in it.

[abc123]

but

if(10=2){hi;}{bye;}


is so much neater..

oh well.

[sde]

thanks redhead that is a good point ..

so you are saying that it is just the equivelent to:

if(condition 1)
{
expression1;
} else {
expression1;
}

and that is not saving you if/else statements, .. it's just saving you 1 if else statement.

... i guess it's useful as shorthand .. also. you can use it even in your cout statement or defining a variable.. i do like that.

i.e. variable = (condition1) ? expression1 : expression2;

or

cout << "the ternary result is " << ((condition1)?expression1:expression2);

i was trying to get it to work in the cout statement for a while the other night, but then i realized you must have the surrounding " ( ) " to make it work.

[redhead]

The nice thing about it, is you can use it in something like:

void* my_function (int is_true)
{
     return (is_true ? 'e' : 10);
}

So if you dont want to do alot of if/else with the returning values, then you can use it as a shortcut..
And the examples you gave are also in that direction, nice and simple..

And the requirement for the sorrounding () in a cout statement is, because '<<' has higher precedence than the '?' operator.