return statement in ternary operator c++

Question

I wrote the absolute function using ternary operator as follows

int abs(int a) {
 a >=0 ? return a : return -a;
}

I get the following er

Answer 1

?: is an operator that takes three expressions and evaluates them in some way to produce a result. return a is not an expression (it's a statement), so your first form doesn't work. It's the same as you can't put return in the arguments of other operators: return a + return b will also not work.

If you want the returns in the separate branches, use if instead:

if (a >=0)
   return a;
else
   return -a;

Answer 2

The second and third arguments to the ternary operator are expressions, not statements.

 return a

is a statement

Answer 3

Your syntax is incorrect. It should be

if (a >=0)
    return a;
else
    return -a;

or the way you wanted it:

return a >=0 ? a : -a;

Answer 4

Return is a statement and cannot be used where a value is expected.

You must use expressions (which usually yield a value) in the three components of the ternary operator.

Answer 5

What's the difference between the two?

One is correct syntax, the other is not.