magic.java

magic square 从各个角相加都是相等的

// Lab 4, Exercise 3 
// Magic square
import java.util.*;

public class Magic {
   
    public int SIZE;
    private int [] magicSquare;
    public Magic (int size)// constructor
{
    SIZE = size;
    magicSquare = new int[SIZE+1];
    for (int i=1; i <=SIZE; i++) magicSquare[i] = 0;
}


   // generate a new square
    public void newSquare()
    {
    int i, j, k;
    boolean repeat;
    magicSquare[1] =  1 + (int) ( Math.random() * SIZE );
    for (i=2; i <= SIZE; i++)
        { 
            do {    
                 repeat = false;     
                 k=  1 + (int) ( Math.random() * SIZE );
                 magicSquare[i] = k; 
               }  while ( repeat(1, i, k ) );
         }
    }// end  newSquare   

    public void printSquare()
    {
        for (int i=1; i<=SIZE; i++)
        {
            if (i%3 == 1 ) System.out.println();
            System.out.print(magicSquare[i] +"   ");
        }
    }  
 
   //return true if newNumber already exists
   public boolean repeat (int first, int current, int newNumber)
   {
       boolean again = false;
       for (int i = first; i < current; i++)
        if ( magicSquare[i] == newNumber) 
            again = true;
       return again;
   }
 
 
    public boolean testMagic(  )
    {
        boolean itIsMagic = false;
        if ((magicSquare[1] + magicSquare[2] + magicSquare[3]== 15) &&
            (magicSquare[4] + magicSquare[5] + magicSquare[6]== 15) &&
            (magicSquare[7] + magicSquare[8] + magicSquare[9]== 15) &&
            (magicSquare[1] + magicSquare[5] + magicSquare[9]== 15) &&
            (magicSquare[7] + magicSquare[5] + magicSquare[3]== 15) )
            itIsMagic = true;
        return itIsMagic;
    }


}