Im just wondering that some people telling that halving is over but according to this website
http://www.bitcoinblockhalf.com/199 days before halving is over.
I dont really understand that some people saying if bitcoin halving is over the price will increase but according to the website above "the coin reward will decrease from 25 to 12.5 coins."
Which is true?
-the price should increase after halving is over or it will increase?
You are making confusion with terms and times. Halving is the produce of bitcoin in blocks with 12.5 bitcoin each and not at 25 bitcoins each as it is now and will be since the moment when will begin the halving. This moment will happen after the production of other 28 477 other blocks (in this moment that I am making this post). Knowing that every block is produced approximately every 10 minutes can be calculated a theoretical time in which will happen the above phenomenon named "halving". So in the market will be not more 25 bitcoins after 10 minutes bout only 12.5 bitcoin. The halving begin in the moment in which will be produced the first block with 12.5 bitcoin and will finish after four years after another halving (from 12.5 at 6.25).
Halving, theoretically must bring increase of the price of bitcoin because the bitcoin market will have less supply (less bitcoin) compared to before in the same amount of time (within ten minutes). Assuming that the demand (who want to buy bitcoin) would be the same (since now don't exist any kind of data that can show some known reason that can change it) must be increase of price. When something is asked by the market (people need and want to buy or have something) and the market have not enough amount from that what is asked (in our case will be only half of the previous amount of bitcoin) exist an simple economic rule that tell that the price of the "something" which is asked will increased for sure.
Anyhow this is never a sure thing. Because, in our above case, there can be created to many other factors which can affect (even hardly) the market and the demand (because the supply if fixed by the technology and cannot be changed in the case of bitcoin) and this can change everything. But normally the above process (named shortly as "halving") must bring increase of the price of bitcoin.