CMPS 200 Homework Assignment 2, Fall 2012

Faculty of Arts & Sciences Department of Computer Science CMPS 200—Introduction to Programming Assignment 2 – Due Monday Oct 8, 2012 Reading Material  Nested for loops: pp 119-136 of the text.  Methods that take arguments and return values: sections 3.1 and 3.2, pp 156-179. Exercises 1. Write a program Triangle to produce the output shown in 8 on page 149 of your book. 2. Write a program Factorials that print the factorials of the odd numbers between 1 and 10. Your program should contain a method that returns the factorial of an integer: public static int factorial(int n) 3. Write a program Payments to calculate the monthly payments you would have to make over a given number of years to pay off a loan at a given interest rate compounded continuously. Your program should contain a method that takes the number of years t, the principal P, and the annual interest rate r as arguments. The desired value is given by the formula (P ert)/(t*12). Use Math.exp(). The signature of the method is: public static double monthlyPayment(double years, double principal, double rate) Use the method to generate a table of the monthly payments one would have to make for a $20,000 loan over 5 years at interest rates varying from 5% to 8% in 0.25% increments. 4. Write a program Fibonacci12 that computes and prints the first 12 Fibonacci numbers as described in Exercise 3 on page 148 of your textbook. Your program should consist of a method public static fibonacci(int n) that prints the first n Fobonacci numbers and gets called from the main() method. 5. Write a program LetterArrow that draws an arrow using the letter b. Your program should contain a method with the following signature: public static void printArrow(String str) which draws an arrow using a given string argument. > java LetterArrow b b b b b 6. Write the method printGrid that prints a grid of integers in column major order as described in Exercise 5 on p.208: public static void printGrid(int rows, int columns) Use it in a program Grid46 that prints a 4x6 grid. 7. Write the following two methods: public static int lastDigit(int number) public static int nthDigit(int number, int n) The methods should return the last digit of a number, and the digit that is n positions away from the last, respectively. When n = 0 we get the last digit, when n=1 we get the next-to-last digit, etc. Use these methods to write a program Digits which prints the last and next-to-last digits of all the numbers that are powers of 2 in the range 2^0 -- 2^12. 8. Write a method nRandom that takes an integer n as argument and uses Math.random() to print n uniform random values between 0.0 and 1.0, and then prints their average value. Introduction to Computer Programming (CMPS 200) Fall 2012 2 of 2 Submission Instructions and Notes  As usual, submit your commented source code and sample runs in a zip file to Moodle by the deadline.  Important: We have changed the naming convention for your submitted files so it has a prefix indicating your section number. Your zip submissions should be named s#_asst2_netid, where # is your section number (between 1 and 9) and netid stands for your AUBnet user name. For example, if your AUBnetid is abc65 and you are in section 4, you should call your submission s4_asst2_abc65. The zip files will be processed automatically so please make sure you use this naming convention.  For those of you using Windows, we will start using notepad++ to edit java programs. Please download from Moodle and install the proper version for your OS (32- or 64-bit). We will continue to use textedit on Mac OS.