A quick N-Queens solver.

Crazy Queens.cpp

#include <iostream>
#include <stdlib.h>
#include <time.h>

#define QUEENS 8

using namespace std;

class Board {
	
	private:
		
		char board[QUEENS][QUEENS];
		int placed;
		
		int safe(int x, int y);
		int filled();
		void print_board();
		void place_queen(int x, int y);
		void clear();
		
	public:
		
		Board();
		int run();
};

Board::Board() {
	int i, j;
	
	for(i = 0; i < QUEENS; i++)
		for(j = 0; j < QUEENS; j++)
			board[i][j] = '.';
	
	placed = 0;
	
	run();
}

int Board::safe(int x, int y) {
	return board[x][y] == '.';
}

int Board::filled() {
	
	int i, j;
	
	for(i = 0; i < QUEENS; i++)
		for(j = 0; j < QUEENS; j++)
			if(board[i][j] == '.')
				return 0;
	
	return 1;
}

void Board::print_board() {
	
	int i, j;
	
	for(i = 0; i < QUEENS; i++) {
		for(j = 0; j < QUEENS; j++)
			cout << board[i][j] << "    ";
		
		cout << "\n";
	}
}

void Board::place_queen(int x, int y) {
	
	int i, j;
	placed++;
	
	for(i = 0; i < QUEENS; i++)
		for(j = 0; j < QUEENS; j++) {
			if(i == x && j == y)
				board[i][j] = 'Q';
			
			else if(x == i || y == j || i + j == x + y || abs(i - x) == abs(j - y))
				board[i][j] = '*';
		}
}

void Board::clear() {
	
	int i, j;
	
	for(i = 0; i < QUEENS; i++)
		for(j = 0; j < QUEENS; j++)
			board[i][j] = '.';
	
	placed = 0;
}

int Board::run() {
	srand(unsigned(time(NULL)));
	
	int a, b;
	
	while(1) {
		
		while(!filled()) {
			a = rand() % QUEENS;
			b = rand() % QUEENS;
			
			if(safe(a, b))
				place_queen(a, b);
		}
		
		if(placed == QUEENS) {
			print_board();
			return 1;
		}
		
		clear();
	}
}

int main() {
	
	Board b;
	
	return 1;
}