8 Queens Chess Problem

#include<bits/stdc++.h>

using namespace std;

int queen[20],line;

int column[20],diagonal1[40],diagonal2[40],a,b;

void Eight_Queen(int _at,int n)
{
    int i;

    if(_at==n+1 && queen[b]==a)
    {
        printf("%2d     ",++line);

        for(i=1; i<=n; i++)
        {
            printf(" %d",queen[i]);
        }

        puts("");

        return ;
    }

    for(i=1; i<=n; i++)
    {
        if(column[i] || diagonal1[i+_at] || diagonal2[n+i-_at])
            continue;

        queen[_at] = i;

        column[i] = diagonal1[i+_at] = diagonal2[n+i-_at] = 1;

        Eight_Queen(_at+1,n);

        column[i] = diagonal1[i+_at] = diagonal2[n+i-_at] = 0;
    }
}

int main()
{
    int test;

    scanf("%d",&test);

    while(test--)
    {
        scanf("%d%d",&a,&b);

        printf("SOLN       COLUMN\n");

        printf(" #      1 2 3 4 5 6 7 8\n\n");

        line = 0;

        Eight_Queen(1,8);

        if(test)
        {
            puts("");
        }
    }

    return 0;
}