n-QUEEN'S PROBLEM USING BACKTRACKING

/*This program is to implement n-queen's problem using backtracking*/
#include<stdio.h>
#include<conio.h>
#include<math.h>
#include<process.h>

int board[20];
int count;
void main()
{
int n,i,j;
void queen(int row, int n);
clrscr();
printf("\n\t Program for queen's using backtracking");
printf("Enter number of queen's ");
scanf("%d",&n);
queen(1,n);                                      //trace using backtrack
getch();
 }


/*This function is for printing the solution to n-queen's problem*/
void print_board(int n)
{
int i,j;
printf("\n\n solution %d:\n\n",++count);
//number of solution
for(i=1;i<=n;i++)
{
printf("\t%d",i);
}
for(i=1;i<=n;i++)
{
printf("\n\n%d",i);
for(j=1;j<=n;j++)        //for n*n board
{
if(board[i]==j)
printf("\tQ");   //Queen at i,j position
else
printf("\t-");   //empty slot
}
}
printf("\n Press any key to continue.....");
getch();
}
/*This function is for checking for the conflicts.If there is no conflict for the desired position it returns 1 otherwise it returns 0*/
int place(int row ,int column)
{
int i;
for(i=1;i<=row-1;i++)
{
//checking for column and diagonal conflicts 
if(board[i]==column)
return 0;
else
if(abs(board[i]-column)==abs(i-row))
return 0;
}
//no conflicts hence Queen can be placed
return 1;
}