Tournament rounds

In a knockout contest, half of the players are out after each round. This function works out how many rounds are needed for a number of players, a whole number from 1 to 1000000.

def rounds(players):
    count = 0
    size = 1
    while size < players:
        size = size * 2
        count = count + 1
    return count

public static int rounds(int players) {
    int count = 0;
    int size = 1;
    while (size < players) {
        size = size * 2;
        count = count + 1;
    }
    return count;
}

(a) State the value the function returns for 16 players. [1]

(b) State the Big O complexity of the function, where n is the number of players. [1]

(c) Explain your answer to (b), using how the loop's counter changes. [2]

[4]