Q2 [5 pts] What does the following code fragment prints when n is 30? Trace the program and show your work to get full credit Stack Integer s = new stack(); while (n > 0) s. push (n 2); n = n/2; ) while (Is.isEmpty()) System.out.print (s.pop(); System.out.println(); Q3 [5 pts] Given a non-negative int n, write and test a recursive function sumDigit that returns the sum of its digits recursively do not use iterations. What is the time complexity for your algorithm? Q4 [10 pts) Write an algorithm that uses a stack (and maybe more than one) to remove all negative integers without changing the order numbers. What is the time complexity for your algorithm? Using the following format for an algorithm Algorithm Title: Input: Output: Algorithm steps: 1. 2. 25 [5 pts) Write an algorithm that converts a Prefix expression into a Postfix expression using a stack. Read the Postfix expression from left to right If the symbol is an operand, then push it onto the Stack If the symbol is an operator, then pop two operands from the Stack Create a string by concatenating the two operands and the operator before them. string = operator + operand2 + operandi And push the resultant string back to Stack Repeat the above steps until end of Prefix expression. Important Note: 1. 2. 3. Your programs should be well-structures and well-documented. Indicate the expected time complexity of Q3 and Q4 You should submit your own code. i.e. you are not allowed to copy from the internet, any other person or references