eight Move q that use OO

[Andres John]

I need help with the legal move of 8 q, i need some ideas or brainstorm about moving the q from 2 diagonal (left and right) and we don't care about the bottom part.
this what i got so far :

public class Queen8Moves{
    private Board b;
    private int dim;
    private int adj[][];
    public  Queen8Moves(){
        //constructor
        this(8);
    }
    
    public  Queen8Moves(int d){
     dim=d;
     b=new Board(dim);
     start(0); // start solving the puzzle by placing a queen in the 0th row
    }
    
    private void start(int r)
    {
        // this recursive method will use backtracking as necessary
        
        for (int c=0; c<dim;c++)// stpe through the columns looking for a legal move
            if (legal(r,c)) // then make the move
                {
                b.setElement(r, c, 1); // a 1 denotes the placement of a queen
                if (r<dim-1)// recursively call start for the next row
                
                    
                {
                     start(r+1);
                     // backtrack by undoing the last move
                     b.setElement(r, c, 0); 
                }
                else
                System.out.println(" ");
                b.printBoard();
                {
                
               ///	 start(r-1);
               //  b.setElement(r, c, 1); 
           //  System.out.println(" ");
                	// we have solved the problem
                    // print the solution and return
                }
                    }
    }
                // if no legal moves then backtrack to previous row

 private int numberOfMoves(int r, int c){
        int ct=0; 
        if (b.getElement(r, c)!=0)
            return 0; 
        for (int i=0; i<7; i++) 
            if (legal(r,c, i)==true )
                ct++;
        
        return ct;               
    } 
    private boolean legal(int r, int c, int d){

        // check the column above and the two diagonals above
    	if (((r + b[d])> dim) || ( r+b[d]<0))
    	    return false; // off the board

    	if (((c + b[d])>dim) || ( c+b[d]<0))
    	    return false; // off the board
    	    
    	if (b.getElement(r + b[d], c + b[d])>0)
    	    return false;
    	    
    	return true;

    }
        public static boolean solve(int size, char[][] b, int r)
        {
                //If all rows have been filled, we have a solution
                if(r>=size)
                {
                        return true;
                }
 
                //For each column(space) on the given row
                for(int c=0; c<size; c++)
                {
                       
                        if(!checkConflict(size, b, r, c))
                        {
                               
                                b[r][c]='Q';
                               
                                boolean success = solve(size, b, r+1);
                               
                                if(success)
                                {
                                       
                                        return true;
                                }
                              
                                else
                                {
                                        b[r][c]='-';
                                }
                        }
                }
                return false;
        }

[fred rosenberger]

Andres John wrote:I need help with the legal move of 8 q, i need some ideas or brainstorm about moving the q from 2 diagonal (left and right) and we don't care about the bottom part.
this what i got so far :

What, exactly, do you need help with? compiling this? running this? is it doing something you don't expect? If so, what DOES it do, and what do you EXPECT it to do?

I don't see an actual question anywhere, so nobody has any idea how to help you.

[Andres John]

fred rosenberger wrote:

Andres John wrote:I need help with the legal move of 8 q, i need some ideas or brainstorm about moving the q from 2 diagonal (left and right) and we don't care about the bottom part.
this what i got so far :

What, exactly, do you need help with? compiling this? running this? is it doing something you don't expect? If so, what DOES it do, and what do you EXPECT it to do?

I don't see an actual question anywhere, so nobody has any idea how to help you.

i guess i need help with the compile and i was expecting the queen to backtracking, the solution requires that no two queens share the same row, column, or diagonal by checking the first row

[fred rosenberger]

so...if you need help with compiling, tell us what happens when you do the "javac Queen8Moves.java" command?

[Andres John]

the error

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
	The method legal(int, int, int) in the type Queen8Moves is not applicable for the arguments (int, int)

	at Queen8Moves.start(Queen8Moves.java:21)
	at Queen8Moves.<init>(Queen8Moves.java:13)
	at Queen8Moves.<init>(Queen8Moves.java:7)
	at Queen8Moves.main(Queen8Moves.java:163)

[fred rosenberger]

ok...so fix that. it tells you exactly what the problem is.

On line 21, you call the legal() method, and pass it two int variables:

if (legal(r,c))

However, the only place you define the legal method, you say it takes THREE int variables:

 private boolean legal(int r, int c, int d)

The compiler is telling you that something isn't right. You either need to:
a) change the call on line 21 to pass in three arguments
b) define a new legal() method that takes two int parameters
c) change the existing legal() method to only take two - this would then require you to change any other calls to the legal() method that currently pass in three arguments.

My guess is you would want to do a, but I haven't (and most likely won't) go through your 100 lines of code to try and figure that out.