/*
Title N Queens problem Author Aditya Author Email ad_online [at] rediffmail.com Description This program finds the locations of placing n queens in a n*n chessboard so that none attack any other Category C++ » Algorithms Hits 496

*/

Code :
#include<iostream.h>
#include<conio.h>
#include<math.h>
#include<process.h>
#include<graphics.h>
class queen
{	int n,x[100];
	public:
		queen();
		void nqueen(int,int);
		int place(int,int);
};
queen::queen()
{
	int k=1;
	textcolor(GREEN);
	cprintf("
Enter the number of queens:");
	cin>>n;
	nqueen( k, n);
}
void queen::nqueen(int k,int n)
{
	for(int i=1;i<=n;i++)
	{
		if(place(k,i))
		{
			x[k]=i;
			clrscr();
			if(k==n)
			{
				for(int j=1;j<=n;j++)
				{textcolor(x[j]);
				gotoxy(1,j);
				cprintf("
queen %d : %d",j,x[j]);
				}
				getch();

				break;
			}
			else
			nqueen(k+1,n);
		}
	}
	return;
}
int queen::place(int k,int i)
{
	int j;
	for(j=1;j<=k;j++)
	{
		if((x[j]==i)||(abs(x[j]-i)==abs(j-k)))
		return 0;
	}
	return 1;
}
void main()
{
	clrscr();
	queen q;
}