Write a program that uses a while loop to calculate and print the multiples of 3 from 3 to 21. Your program should print each number on a separate line. Expected Output:
3
6
9
12
15
18
21
The condition num <= 21 will ensure that the program will only print multiples of 3 up to 21. We set num as 3 since we want to start printing from 3, and we add 3 each time to get the multiples.
