I was practicing with stockfish level 8, having two rooks in the endgame whereas stockfish has only one. At the 78th move, it was declared as a draw. But, it was not a stalemate. Can anyone please help me, finding out why is this a drawn match ?
The game ended because of the 50-Move-Rule.
The fifty-move rule in chess states that a player can claim a draw if no capture has been made and no pawn has been moved in the last fifty moves (for this purpose a "move" consists of a player completing their turn followed by the opponent completing their turn).
The last capture was made by white at move 28. (Rgxg6), so the game is declared a draw on move 78.
You most likely played 50 moves without a capture or a pawn move. This is called the 50-move rule, which results in a draw.
Check back to around move 28. You should see the last capture/pawn move there.