It is more important to be consistent than to select the best.
These styles have different advantages and drawbacks, but none is as bad as mixing them within a project or even a compilation unit or within a function.
Ternary operator is the obvious choice for this specific code. For simple single statement if/else's that can't be otherwise expressed, I'd prefer a properly indented case 3:
if (val % 2 == 1)
output = “Number is odd”;
else
output = “Number is even”;
I understand the motivation behind "always use braces", but I've personally never been bitten by their omission (OK, once. With a macro.)
From the above styles, I'd pick (2). (4) would be ok if "properly" indented.
(1) I'd attribute to a young developer who hopefully will grow out of "compact code", or someone who can't afford a decent monitor. Still, I'd go with it if it was the local style.
