If you have bought stocks in CNC today and if you sell the same on same day it will be considered as intraday.
If your question is regarding how the trade is treated by your broker, it’ll be considered an intraday trade and you’ll be charged brokerage accordingly. The same remains true for the way the trade is treated at the exchange, i.e., it’ll be considered an intraday trade. The only reason you’re asked to actually classify a trade as delivery or intraday while entering it is so your broker can decide how much leverage you get and how much exposure you get. If you declare while entering a trade that you’re going to square it off before the day’s end, the broker has the power to square it off if you don’t and hence cover his exposure, whereas if it’s a delivery purchase, whatever exposure or leverage model your broker has in place for such trades will apply.