CMPS 200 Homework Assignment 6, Fall 2011

Faculty of Arts & Sciences Department of Computer Science CMPS 200—Introduction to Programming Assignment 6 – Due Mon Nov 14, 2011 Notes and Announcements • Material covered this week: Interactive Input, Formatted output • A Frequently Asked Questions (FAQ) sheet about the programming environment is now posted on Moodle. • This assignment relies on the class StdIn.java that you need to install in your working environment. For this week, download the file from Moodle and place it in the same directory where your java code exists (for every program you are writing). Problem 1. MinMax Write a program that reads a number N from the command line and asks the user to enter N integers. The program should compute their minimum and maximum, and prints them out. A sample run is as follows: (user input is displayed in bold) C:> java MinMax 5 Enter integer 1: 3 Enter integer 2: 7 Enter integer 3: -­‐1 Enter integer 4: 90 Enter integer 5: 71 Minimum: -­‐1. Maximum: 90. Problem 2. Average Write program that reads a stream of floating point numbers from standard input, computes and prints their average. Problem 3. Discount Write a program Discount.java that reads in a list of prices from standard input and writes on the standard output a formatted table consisting of three columns as shown below. The first column consists of the prices as read from standard input (in US dollars). The second column prints a discounted price that represents a 1/3 discount on the price. The third column prints the equivalent value in Lebanese Liras rounded to the nearest LL 50 (assume a conversion rate $1 = LL 1508). Your output should have 2 digits after the decimal in the first 2 columns and no decimal in the third. It should also print column headers and makes sure the columns are lined up properly. An example invocation of the program might produce: > java Discount < prices.txt Price Discounted LL Equivalent Price $ 80.00 $53.33 LL 80450 $140.00 $93.33 LL 140750 Introduction to Programming (CMPS 200) Fall 2011 2 of 2 Problem 4. PowersOfN Write a program, PowersOfN, that asks the user to enter a base and an exponent, calls a method named printPowersOfN that accepts the base and exponent as arguments, and prints each power of the base from 1 up to that maximum power, inclusive. For example, consider the following calls: printPowersOfN(4, 3); printPowersOfN(5, 6); These calls should produce the following output: 1 4 16 64 1 5 25 125 625 3125 15625 You may assume that the exponent passed to printPowersOfN has a value of 0 or greater. You are also required to write a method named printPowersOfN_v2 that has the same functionality as printPowersOfN but without using the Math class in your code (Write your own method that uses a for loop to calculate the power of a number). Problem 5. Caesar One of the oldest encryption schemes is attributed to Julius Caesar. Caesar used to send secret messages to his friends using a scheme that is now known as a Caesar cipher. Each letter is replaced by the letter k positions ahead of it in the alphabet (and you wrap around if needed). The table below gives the Caesar cipher when k = 3. For example the message "VENI, VIDI, VICI" is converted to "YHQL, YLGL, YLFL". Write a program Caesar.java that takes a command line parameter k and applies a Caesar cipher with shift = k to a sequence of letters read from standard input. You program should handle lower and upper case letters, and leave other characters unchanged. Hint: To get the k-­‐th next character, one can simply add k to the character. This will not work for the last k characters of the alphabet; they will have to be treated separately. Submission Instructions • As usual, your submission must consist of a zip archive that contains .java files and a single Word document that contains sample runs or notes you may wish to add. The files must be zipped in a file that adheres to the following naming convention asst6_<netid>, where <netid> stands for you AUBnet user name. • Please make sure there are no folders or subfolders in your submitted zip file. When the zip is opened, you should only see .java files and a word file at the top level. Please check your zip before submission. Your zip file must be uploaded to Moodle.