Returning the other argument of 2 possible arguments without using conditions [closed]

Question

For example, if I have a function that is guaranteed to receive either 5 or 7 as an argument, I want the function to return 5 if received 7 and 7 if received 5 without using any conditions.

I was asked this in an interview and was pretty stumped, thanks.

Answer 1

Simple arithmetic:

return 7 - input + 5;

(which can be simplified as return 12 - input;)

Let's say the input is 7:

return 7 - 7 + 5 --> return 5

Or if the input is 5:

return 7 - 5 + 5 --> return 7