1 #include
     
        2 #include
      
         3 #include
       
          4  5 using namespace std;  6  7 queue
        
         q;  8 int main()  9 {
    10     int i, w, h, k, j; 11     int visit[21][21]; 12     char s[21][21]; 13     14     while(scanf("%d%d", &w, &h) != EOF) 15     {
    16        if(w==0 && h==0)  break; 17        getchar(); //此处是为了处理enter换行键，不能省，此处较容易出错，我也是调了两个小时才恍然大悟。 18        for(i=1; i<=h; i++) 19        {
    20          for(j=1; j<=w; j++) 21          {
    22           scanf("%c",&s[i][j]); 23           if(j==w)  getchar();//此处和上述一样为了处理换行符。 24          }  25        } 26        for(i=1; i<=h; i++) 27        {
    28          for(j=1; j<=w; j++) 29          { 30             if(s[i][j]=='@') 31             {
    32               visit[i][j] = 1;//标记后就不能访问了 33               q.push(i); 34               q.push(j);      35             } 36             if(s[i][j]=='#') 37                visit[i][j] = 1；//和上述标记一样 38             if(s[i][j]=='.') 39                visit[i][j] = 0; 40          } 41        } 42        k = 0;   //每次访问结束后队首出队，记录出队多少次，就可知道访问几次，从而可判断访问到了几个',' 43        while(!q.empty()) 44        {
    45           int x, y; 46           x = q.front(); 47           q.pop(); 48           y = q.front(); 49           q.pop(); 50           k++; 51           if(visit[x-1][y]==0 && x-1>=1) 52           {
    53                visit[x-1][y] = 1; 54                q.push(x-1); 55                q.push(y);      56           } 57           if(visit[x+1][y]==0 && x+1<=h) 58           {
    59                visit[x+1][y] = 1; 60                q.push(x+1); 61                q.push(y);     62           }    63           if(visit[x][y+1]==0 && y+1<=w) 64           {
    65                visit[x][y+1] = 1; 66                q.push(x); 67                q.push(y+1);                   68           } 69           if(visit[x][y-1]==0 && y-1>=1)    70           {     71                visit[x][y-1] = 1;   72                q.push(x); 73                q.push(y-1);             74           } 75        } 76        printf("%d\n",k); 77     }  78    return 0;      79 }        80  81