Flip function in Scheme
<p>does anybody know how can I create a function in Scheme that takes no arguments and everytime I call it returns 0 or 1, depending on how many times it's been called? For example, the 1st time returns 1, the 2nd 0, the 3rd 1, etc. </p>

<p>I suppose I have to use a local variable inside the function, but I don't know exactly how, so that it changes value everytime I call it. </p>