Difference between INPUT INT and INPUT DOUBLE



         So i am knew to mql5 and coding in general and i was not able to find a conclusive answer for my question.

The thing is, when i use:

input double   takeprofit = 200;


input int      takeprofit = 200;

  my backtest results returns the same, but when i use Fast genetic based algorithm the results are different

What is the difference between these two?

This is how i am using the "takeprofit".                       

trade.Buy(10, Symbol(), 0, candleL - 10, candleH + takeProfit, "") ;