CpSc 210, Section 1
                             Assignment 3 
                            September 13, 2002 


Due:  Friday, September 20 at 11:59 p.m.  

Total point value of assignment:  50 points
Not accepted late.

This assignment is to be done INDIVIDUALLY.

Assignment:  Complete the method computeNextPrime.  The class PrimeNumbers 
     must be stored in a file named PrimeNumbers.java.  (3 point deduction 
     from grade for failure to name file correctly!)  You may change
     the testing in the main method if you wish.  Do not change any
     methods except computeNextPrime and main.



// CPSC 210
// Assignment #3
// Build prime number array

public class PrimeNumbers
{
   public static void computeNextPrime ( int indexOfLast, int [] primes )
   // pre:  indexOfLast >= zero and prime[0] will contain 2
   //       If indexOfLast > zero, primes are sequentially stored
   // post:  computes the next prime number after primes[indexOfLast] and
   //        stores this value in the array primes
   {
      // code goes here    
      // with the initialization shown in the main program,
      // the first time this method is called primes[6] will be set to 17
   }

   public static void printPrimes ( int indexOfLast,  int [ ] primes )
   // print primes[0]  .. primes[indexOfLast]
   {
      System.out.println ("The first " + (indexOfLast+1) + " primes are: ");
      for (int k = 0 ; k <= indexOfLast ; k++ )
         System.out.print("  " + primes[k]);
      // k > indexOfLast

      System.out.println();
   }

   public static void main ( String [ ] args )
   { 
      // an array to hold integers that represent prime numbers
      int maxSize = 501;
      int [ ] primes = new int [maxSize];

      // start filling the array of prime numbers
      primes[0] = 2;
      primes[1] = 3;
      primes[2] = 5;
      primes[3] = 7;
      primes[4] = 11;
      primes[5] = 13;
      int indexOfLastPrime = 5;

      printPrimes (indexOfLastPrime, primes);

      // compute and store 10 more primes
      int increment = 10;
      int newCount = increment + indexOfLastPrime;
      while ( indexOfLastPrime <= newCount )
      {
         computeNextPrime(indexOfLastPrime++, primes);
         printPrimes (indexOfLastPrime, primes);
      }
      // indexOfLastPrime > newCount
   }
}


Also, a test case you should run is 
      primes[0]=2;
      intindexOfLastPrime = 0;


Grading Rubric:

	5 pts. reasonable attempt to solve problem as assigned
	5 pt. also compiles
	5 pts. style standards (includes clarity)
       (1) Your name must be printed as a comment at the beginning of file.
       (2) A description of what this program does must immediate follow name.
       (3) Indent exactly 3 or 4 spaces.  Be consistent.  See handout examples.
       (4) Every Java statement must begin on a separate line.
       (5) The first operation of your program must be to print your name,
           followed by "CPSC 210", the assignment number, and a description 
           of what program does.
       (6) A comment must immediately follow all while, do, or for loops
           giving the condition that is true after loop exit.

    The following 35 points are available only for code that compiles 
    and runs without error. 

      5 pts. main as given gives correct 
      5 pts. main (primes[0]=2; indexOfLastPrime=0;) gives correct result
     10 pts. program works correctly (with our code).  
     15 pts. overall quality of program  (i.e., ease of reading and
            understanding code, choice of algorithm including use of
            necessary/unnecessary looping, etc.)