Program in C to Find 'N' Queens on an "N x N" Board

 A.K.A - "N-Queens Problem"

(Note: I computed till 15. N-Queens is only defined for  N>= 4)

 Manipulate the constant named "MAX"

Program:

#include<stdio.h>
#include<conio.h>
#define MAX 8
int q[MAX] = { 0 };

void printem()
{
        int i, j,k;

        for (i = 0; i < MAX; i++) {

        printf("\n\t");

        for (j = q[i], k = MAX - j; j > 0; j--) {

            printf("-");
        }

        printf("X");

        for (; k > 0; k--) {

            printf("-");
        }

 }//Outer for ends
}

int dist(int x, int y)
{

 if (x > y)
        return (x - y);
 return (y - x);
}

int match(int i, int j)
{

    int k, xi, xj;
    for (k = 0; k < i; k++) {
      
       xi = k;
       xj = q[k];

       if (xi == i || xj == j)
            return (0);
       if (dist(i, xi) == dist(j, xj))
            return (0);
    }
    for (; k < MAX; k++) {
        q[k] = -1;
    }
    return (1);
}

int main()
{

    int i = 0, k, ci, cj;
    clrscr();
    for (k = 0; k < MAX;) {

       if (i >= MAX)  // My Version of Back tracking
       {
           printf("nBackTracked... %dth Queen", k + 1);
           k--;
           while ((q[k] + 1) >= MAX)
                 k--;
           i = q[k] + 1;
       }

       ci = i++;

       if (match(k, ci) == 1) //k - x axis. ci - y axis.
       {
            i = 0;
            q[k] = ci;
            k++;
       }
    } // for loop ends
    printf("nThe Queens: ");
    for (i = 0; i < MAX; i++)
       printf("n%d: %d", i + 1, q[i]);

    //printem(); //remove comment to see how it looks on the board
    getch();
}