Go: ///
// File:  1160.go
// Author: ymiyamoto
//
// Created on Sun Mar  4 20:45:57 2018
//
package main

import (
	"fmt"
)

var w, h int
var graph [][]string

func dfs(visited [][]bool, x, y int) {
	visited[x][y] = true

	for i := -1; i <= 1; i++ {
		for j := -1; j <= 1; j++ {
			dx := x + i
			dy := y + j
			if 0 <= dx && dx < h && 0 <= dy && dy < w && graph[dx][dy] == "1" && !visited[dx][dy] {
				dfs(visited, dx, dy)
			}
		}
	}
}

func main() {
	for {
		fmt.Scan(&w, &h)
		if w == 0 && h == 0 {
			break
		}

		graph = make([][]string, h)
		for i := range graph {
			graph[i] = make([]string, w)
		}

		for i := 0; i < h; i++ {
			for j := 0; j < w; j++ {
				var s string
				fmt.Scan(&s)
				graph[i][j] = s
			}
		}

		visited := make([][]bool, h)
		for i := range visited {
			visited[i] = make([]bool, w)
		}

		count := 0
		for i := range graph {
			for j := range graph[i] {
				if graph[i][j] == "1" && !visited[i][j] {
					dfs(visited, i, j)
					count++
				}
			}
		}

		fmt.Println(count)
	}
}

C++: #include<iostream>
using namespace std;
void dfs(int,int);
int box[50][50];
int main(){
  int w,h,i,I,a;
  while(1){
    a=0;
    cin>>w>>h;
    if(w==0&&h==0) break;
    for(i=0;i<=h+1;i++){
      for(I=0;I<=w+1;I++){
	box[i][I]==0;
      }
    }
    for(i=1;i<=h;i++){
      for(I=1;I<=w;I++){
	cin>>box[i][I];
      }
    }
    for(i=1;i<=h;i++){
      for(I=1;I<=w;I++){
	if(box[i][I]==1){
	  dfs(i,I);
	  a++;
	}
      }
    }
    cout<<a<<endl;
  }
  return 0;
}
  void dfs(int i,int I){
  if(box[i][I]==0) return;
  box[i][I]=0;
  dfs(i,I+1);
  dfs(i+1,I+1);
  dfs(i+1,I);
  dfs(i+1,I-1);
  dfs(i,I-1);
  dfs(i-1,I-1);
  dfs(i-1,I);
  dfs(i-1,I+1);
  }

C++: #include <bits/stdc++.h>
using namespace std;
using ll=long long;
typedef pair<int,int> P;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
int w,h;
int nx,ny;
void dfs(vector<vector<int>> &G,int a,int b){
    G.at(a).at(b)=0;
    
    for(int k=-1;k<=1;k++){
        for(int l=-1;l<=1;l++){
            nx=a+k;
            ny=b+l;
        if(0<=nx&& nx<h && 0<=ny&& ny<w && G.at(nx).at(ny)==1) dfs(G,nx,ny);
        }
    }
    return ;
}



int main(){
    int w,h;
    cin>>w>>h;
    vector<vector<int>>G(h,vector<int>(w));
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            cin>>G.at(i).at(j);
        }
    }
    int count=0;
    for(int i=0;i<h;i++){
        for(int j=0;j<w;j++){
            if(G.at(i).at(j)==1){
                dfs(G,i,j);
                count++;
            }
        }
    }
cout<<count<<endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
bool d[51][51];
int a,b,s,_x,_y,dx[8]={0,-1,-1,-1,0,1,1,1},dy[8]={1,1,0,-1,-1,-1,0,1};
#define r(z,x) for(int z=0;z<x;z++)
void bfs(int x,int y){
	if(0>x||x>=b||0>y||y>=a)return;
	d[x][y]=0;
	r(i,8)if(d[_x=x+dx[i]][_y=y+dy[i]])bfs(_x,_y);
}
int main(){
	while(cin>>a>>b,a||b){
		s=0;
		r(i,b)r(j,a)cin>>d[i][j];
		r(i,b)r(j,a)if(d[i][j])bfs(i,j),s++;
		cout<<s<<endl;
	}
}

C++: #include <iostream>
#include <vector>
using namespace std;
int ans;
int w, h;
//?§???????
vector<int> vx {-1, 0, 1, -1, 1, -1, 0, 1 };
vector<int> vy { 1, 1, 1, 0, 0, -1, -1, -1 };
vector<vector<int>> area;
int islands = 0;

//????±????????????¨????????¢?´¢
void dfs(int i,int j){
	for (int n = 0; n < vx.size(); n++){
		int x = j + vx[n];
		int y = i + vy[n];
		if (x >= 0 && x < w &&
			y >= 0 && y < h &&
			area[y][x] == 1){
			area[y][x] = 2;
			dfs(y,x);
		}
	}
}

int main(){
	while (1){
		cin >> w >> h;
		if (w == 0 && h == 0) break;
		//?????????
		islands = 0;
		area.clear();
		area = vector<vector<int>>(h, vector<int>(w));
		//??\???
		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				cin >> area[i][j];
			}
		}
		//??¨??¢?´¢
		for (int i = 0; i < h; i++){
			for (int j = 0; j < w; j++){
				if (area[i][j] == 1){
					islands++;
					area[i][j] = 2;
					dfs(i, j);
				}
			}
		}
		cout << islands << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <vector>

using namespace std;

#define rep(i,a) for(int i=0;i<a;i++)

int di[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dj[] = {-1,  0,  1,-1, 1,-1, 0, 1};
int field[60][60];
int w, h;
bool inrange(int i, int j){
    return i >= 0 && j >= 0 && i < h && j < w;
}

void rec(int i, int j){
    field[i][j] = 0;
    rep(k, 8){
        int ni = i+di[k];
        int nj = j+dj[k];
        if(inrange(ni, nj) && field[ni][nj] == 1){
            rec(ni, nj);
        }
    }
}


int main(){
    int n,p;
    while(cin>>w>>h,w||h){
        rep(i, h){
            rep(j, w){
                cin >> field[i][j];
            }
        }
        int ans = 0;
        rep(i, h){
            rep(j, w){
                if(field[i][j] == 1) {
                    rec(i, j);
                    ans++;/*
                    rep(a, h) {
                        rep(b, w){
                            cout << field[a][b] << " ";
                        }
                        cout << endl;
                    }
                    cout << endl;*/
                }
            }
        }
        cout << ans << endl;
    }
}