Lab - IV (10 February 2017)

Preliminaries:

This lab is about Java Programming. It has three sets of exercises: modifying the Java Classes discussed in the class(!); writing simple Java programs; and, designing Classes using the guidelines given in the class.

The following pieces of code may be used to start your exercises:

Problems

The following problems make modifications to the code given above.
  1. Read an integer directly instead of reading it as a String and then converting it into an integer using Integer.parseInt()
  2. If the input given by the user is either 1, 2, 5 or 10, display them as Roman numerals I, II, V and X respectively. You need to modify the symbol map in this case.

The following problems need you to write simple Java programs.

  1. Read in a string from the user and your program should print The string is a valid roll number if it is a correct roll number for any student in your class. Otherwise, it should output Invalid Input.
  2. It is given that 1 January 2000 fell on a Saturday. Ask users to input a year between 2000 and 2999 (both inclusive) and output the day of the week of 1 January of that year. The logic for implementation is:
    • Day of the week advances by one for each non-leap year and by two for each leap year. Thus, 1 January 2001 will be on Monday(Saturday + 2) while 1 January 2004 will be on Thursday (Monday + 3).
    • For a given year, add as many days as the number of years from 2000 and then add the correct number of days for leap years which occur once every four years. For 2004, we would add 4 days (2004 - 2000) and 1 day for the one leap year (2000) to add a total of 5 days. Saturday + 5 = Thursday.
    You can verify whether your answer is correct by using the Linux command cal as follows:
    cal 1 year
    If will output the calendar for January of the specified year. For example, cal 1 2020 outputs the following.

        January 2020      
Su Mo Tu We Th Fr Sa  
          1  2  3  4  
 5  6  7  8  9 10 11  
12 13 14 15 16 17 18  
19 20 21 22 23 24 25  
26 27 28 29 30 31
  3. Create a 2D array of size 10x15 and fill it with random values between 0 and 100. Ask the user to input a number between 0 and 100 and print the array location where it first occurs. If it does not occur at all, then output an appropriate message. Implement this program (a)using only break and (b)using labelled break.

    You can generate random numbers as:

    int random_number;
    Random rand = new Random();
    random_number = rand.nextInt(100) + 1

The following problems ask you to define classes. You need not implement them.

  1. Define a class Book such that it contains useful information for a buyer.
  2. Define a class VisitingCard for the printer, and for a user.
  3. Define a class TVRemote for the user.
  4. Define a class MovieSong for a Quiz participant on movie songs.
In these problems, make sure you think about when to define set/get methods, when to use the constructor and when to use general methods.
THE END