Suppose, I buy XRP and set limit of 15% fluctuation. The coin should immediately be converted into Monero if this happens. Is there any exchange which offers this function ?
You mean if you set on a sell order? You could set a stop loss and target sell, andcompute what is the 15% fluctuation of that in both up and down movement. Yes thats possible on exchange but its not depend on the percentage but only on the target price. Likewise, you could compute that yourself which is pretty basic math at all.