Working with numbers between 2 variables given in input

Question

how do i work with numbers given in input? (example: given n1 and n2 in input, find all the multiple of 3 between n1 and n2)

Answer 1

You can do a loop that starts in n1 (or n1 + 1 If you want to use just the numbers between) and ends in n2 (or n2 - 1, for the same reason that i said before).

Answer 2

Using your example: create a counter to add when you find a multiple of 3, then make this loop:

for(int i = n1 + 1; i < n2; i++) {
if(i % 3 == 0) {
counter++; //equivalent to counter = counter+1
}
}