Is there a better way of writing v = (v == 0 ? 1 : 0);

Ollie Glass picture Ollie Glass · Aug 2, 2011 · Viewed 60.8k times · Source

I want to toggle a variable between 0 and 1. If it's 0 I want to set it to 1, else if it's 1 I want to set it to 0.

This is such a fundamental operation that I write so often I'd like to investigate the shortest, clearest possible way of doing it. Here's my best so far:

v = (v == 0 ? 1 : 0);

Can you improve on this?

Edit: the question is asking how to write the above statement in the fewest characters while retaining clarity - how is this 'not a real question'? This wasn't intended to be a code-golf exercise, though some interesting answers have come out of people approaching it as golf - it's nice to see golf being used in a constructive and thought-provoking manner.

Answer

Guffa picture Guffa · Aug 2, 2011

You can simply use:

v = 1 - v;

This of course assumes that the variable is initialised properly, i.e. that it only has the value 0 or 1.

Another method that is shorter but uses a less common operator:

v ^= 1;

Edit:

To be clear; I never approached this question as code golf, just to find a short way of doing the task without using any obscuring tricks like side effects of operators.