CIS 3022
Practice Lab

Introduction

A magic square is an n-by-n grid of integers with the property

• every column,
• every row, and
• both diagonals

when added up sum to the same constant. For instance, for this simple magic square the constant is (obviously) 15.

A normal magic square has the additional property that it contains all the integers from 1 to n squared. Thus

is a “non-normal“ magic square.

Problem statement

Implement and test a class that determines whether or not a square is “magic.” The method testAllCandidates( String filename ) shall open the specified file, each line of which contains the int values that comprise a single candidate. For each candidate, print the square (columns separated by TABS) and on the final row (one TAB after the last column) either

• “is not a magic square“
• “is non-normal but magic (constant sum)“ or
• “is magic (constant sum)“

followed by 2 newline characters. For example, the input file:

16 3 2 13 5 10 11 8 9 6 7 12 4 15 14 1
1 1 1 1
1 2 3 4

would result in this output:

16	3	2	13
5	10	11	8
9	6	7	12
4	15	14	1	is magic (34)


1	1
1	1	is non-normal but magic (2)


1	2
3	4	is not a magic square

Notes and hints

• You may assume that all candidates are squares, ranging in size from 1-by-1 to 10-by-10.
• You should be asking yourself: what is the offset from the beginning of the data to the start of row y? Once you've figured that out: what is the offset from the beginning of the data to column x in row y?
• Here are some more valid examples:

  6 32 3 34 35 1 7 11 27 28 8 30 19 14 16 15 23 24 18 20 22 21 17 13 25 29 10 9 26 12 36 5 33 4 2 31
  4 14 15 1 9 7 6 12 5 11 10 8 16 2 3 13
  22 47 16 41 10 35 4 5 23 48 17 42 11 29 30 6 24 49 18 36 12 13 31 7 25 43 19 37 38 14 32 1 26 44 20 21 39 8 33 2 27 45 46 15 40 9 34 3 28
  37 78 29 70 21 62 13 54 5 6 38 79 30 71 22 63 14 46 47 7 39 80 31 72 23 55 15 16 48 8 40 81 32 64 24 56 57 17 49 9 41 73 33 65 25 26 58 18 50 1 42 74 34 66 67 27 59 10 51 2 43 75 35 36 68 19 60 11 52 3 44 76 77 28 69 20 61 12 53 4 45
  

• Guess what a new Scanner( aStringReference ) does? That's right... it scans for tokens within that String!
• Hint: Look for mathematical relationships (simple formulae) that describe all (or part) of an output line.
• Warning: The output must be computed by your program. Hard coding the output for different cases not an acceptable solution for this quiz.
• While not required, it is strongly recommended that you do an analysis and design before coding.
• This class contains some reminders and some techniques that you'll need to do this lab.

  import java.util.ArrayList;
  import javax.swing.JOptionPane;
  import java.util.Scanner;
  import java.io.File;
  import java.util.HashMap;
  
  public class PracticeLab
  {
      private ArrayList data;       // hints: get/add/size
      private HashMap map; // hints: get/put/containsKey
  
      // extract an int from a String (e.g., "123" would return 123) 
      public int stringToInt( String s )
      {
          return Integer.parseInt( s );
      }
  
      // demonstrates how to get a String from the user
      public void demo()
      {
          String name = JOptionPane.showInputDialog( "What is your name?" );
          System.out.println( "Hi, " + name + "!  Pleased to meet you!" );
      }
  
      public void tryThis()
      {
        System.out.println( "What\tdoes\tthis\n\tprint?" );
      }
  
      public void printFile( String filename )
      {
        Scanner scan = null;   // hints: hasNext/next/hasNextLine/nextLine
        try
        {
          scan = new Scanner( new File( filename ) );
        }
        catch ( java.io.FileNotFoundException e )
        {
          System.out.println( "Couldn't open " + filename );
          System.exit( -1 );  // terminate the program
        }
  
        while ( scan.hasNextLine() )
        {
          System.out.println( scan.nextLine() );
        }  
      }   
  }
  

Treat this like a QUIZ

Remember: the quizzes are closed book, closed notes, and closed internet. You may use only those files that are provided as part of the quiz (if any) and files that you write during that quiz period.