What does the following loop do?

int[] a = {6, 1, 9, 5, 12, 3};
int len = a. length;
int x = 0;
for (int i = 0; i < len; i++)
if (a[i] % 2 == 0) x++;
system. out. println(x);

1. sums the even elements in a.
2. finds the largest value in a.
3. counts the even elements in a.
4. finds the smallest value in a

Which of the following “invisible” marks represents an inserted tab?

Suppose s, t, and w are strings that have already been created inside main. write a statement or statements, to be added to main, that will determine if the lengths of the three strings are in order by length, smallest to largest. that is, your code should determine if s is strictly shorter than t, and if t is strictly shorter than w. if these conditions hold your code should print (the boolean value) true. if not, your code should print false. (strictly means: no ties) example: if s, t, and w are "cat", "hats", and "skies" your code should print true - their lengths are 3-4-5; but if s, t, and w are "cats" "shirt", and "trust", then print false - their lengths are 4-5-5 enter your code in the box below

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?