Is there any Cryto exchange that supports automatic sale when profit above X % and buy again when price drop to previous price and repeat this cycle? I am new to bitcoins 

I got a new idea in short selling bitcoins 

That is , imagine the price of 1 BTC = $1000

I will buy 0.5 BTC for $500

Now I will wait till the price increased by 10% that is , $1100

Now my portfolio becomes $550

.....

Now I will sell the 0.5 BTC for $550 . I got 10 % , $50 profit

Now I will wait till the price again goes below 10% , that is $1000 .

Now I will buy when price again reached to $1000 for the $550 , that is for the total gain.

then the above cycle continues ...



Suppose if the buy price never reach, that is price starts to grow then I will buy for day's or week's low.. and continue the cycle

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Is there any exchange that support this automatic job flow ?
I think it will be better to divide your deposit into two parts. Half in USD and another half in BTC. First bot tries to maximize your profit in USD. Second - in BTC. Any price moving makes you rich