hdu 1312 red and black

#include <stdlib.h>
#include <string.h>
int W,H;
int sum;
char map[50][50];
int find[50][50];
typedef struct{ int x,y;} node;
int iPlus[4] = {-1,0,1,0};
int jPlus[4] = {0,-1,0,1};
void (node p)
{
    int k;
    find[p.x][p.y] = 1;
    node next;
    sum++;
    for ( k = 0; k < 4; k++)
    {
        next.x = p.x + iPlus[k];
        next.y = p.y + jPlus[k];
        if ( next.x >= 1 && next.x <= H && next.y >= 1 && next.y <= W)
        {
            if ( map[next.x][next.y]=='.' && !find[next.x][next.y] )
                DFS(next);
        }
    }
}
int main()
{
    freopen("Sample Input.txt","r",stdin);
    system("Color F0");
    int i,j,k;char ch;
    node stand;
    while ( scanf("%d%d",&W,&H),W&&H)
    {
        getchar();
        for ( i = 1; i <= H; i++)
        {
            for ( j = 1; j <= W; j++)
            {
                scanf("%c",&ch);
                if ( ch=='@') { stand.x = i; stand.y = j;}
                map[i][j] = ch;
            }
            getchar();
        }
        sum = 0;
        memset(find,0,sizeof(find));
        DFS(stand);
        printf("%dn",sum);
    }
    getch();
    return 0;
}