CMPS 200 Homework Assignment 4, Fall 2012

Faculty of Arts & Sciences Department of Computer Science CMPS 200—Introduction to Programming Assignment 4 – Due Friday Oct 19, 2012 Notes and Announcements  Reading Material: review Chapters 1-4.  This assignment is exceptionally due this week on Friday Oct 19 at 8:00pm.  A reminder that the first exam will take place on Saturday Oct 20, 2011, 9:00-11:00am, in Bliss Hall.  Attached are the APIs you may need during the exam. A copy of this page will be distributed to you. The exam is closed-book and closed-notes otherwise. No access to any local or internet recourses is allowed.  You may use your own laptop during the exam, but you have to make sure it has enough battery power to last you for the whole exam period.  We will have a “Programming Clinic” open to all on Friday 2:00-5:00pm in Bliss 209. This is intended to provide additional help and you are encouraged to take advantage of it as needed. Exercises 1. Triangle. Write a program Triangle.java that takes one command line parameter N and prints out a two dimensional N-by-N triangular pattern as shown below. (Hint. Think about the pattern's structure). * * * * * * . * * * * * . . * * * * . . . * * * . . . . * * . . . . . * 2. RandomString. Write a program that takes a positive integer N and a string as command line arguments (N is assumed to be smaller than the length of the string). The program should pick N random characters from the string and construct and print a new string composed of these random characters. 3. RemoveSpaces. Write a method removeSpaces that accepts a string as argument and returns a string with the white space characters removed from it (the method should not print anything to the console). The signature of the method should be: public static String removeSpaces(String str) Hint: The method should build a string one character at a time using the + operator, starting with the empty string ””. Use this method to write a program above that takes an integer command line argument N followed by N strings and prints each of the strings without spaces. Hint: The strings must be quoted on the command line. 4. Palindromes. Write a method isPalindrome that accepts a string as argument and returns true or false indicating if the string is a palindrome or not. A palindrome is a string that can be read the same way forward and backward. Your method must handle upper and lower case characters (the string “Madam” is a palindrome). The signature of the method should be: public static boolean isPalindrome(String str) You are not allowed to generate a new string in the your implementation of this method. Rather, you should walk through the string to determine if is a palindrome or not. Hint: Use the method Character.toLowerCase() and/or one or more of the other methods on variables of type char; see page 280 of your textbook. Use this method to write a program Palindromes that takes an integer command line argument N followed by N strings and prints the strings that are palindromes. Submission Instructions As usual, submit your commented source code and sample runs in a zip file named s#_asst4_netid, where # is your section number (between 1 and 9) and netid stands for your AUBnet user name. Introduction to Computer Programming (CMPS 200) Fall 2012 2 of 2