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>
#include <vector>
#include <array>
#include <list>
#include <queue>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <string>
#include <sstream>
#include <algorithm>
#include <random>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <cmath>
#include <cassert>
#include <climits>
#include <thread>

using namespace std;

void add_one(queue<pair<int, int>>& dst, int c_h, int c_w, int h, int w)
{
	if (c_h < 0 || h <= c_h || c_w < 0 || w <= c_w) return;

	dst.push(make_pair(c_h, c_w));
}

void solve_one(vector<vector<bool>>& map, int h, int w, int s_h, int s_w)
{
	queue<pair<int,int>> checks;
	checks.push(make_pair(s_h, s_w));

	while (!checks.empty()) {
		auto cur = checks.front();
		checks.pop();

		if (!map[cur.first][cur.second]) continue;

		map[cur.first][cur.second] = false;

		add_one(checks, cur.first + 1, cur.second    , h, w);
		add_one(checks, cur.first - 1, cur.second    , h, w);
		add_one(checks, cur.first    , cur.second + 1, h, w);
		add_one(checks, cur.first    , cur.second - 1, h, w);
		add_one(checks, cur.first + 1, cur.second + 1, h, w);
		add_one(checks, cur.first + 1, cur.second - 1, h, w);
		add_one(checks, cur.first - 1, cur.second + 1, h, w);
		add_one(checks, cur.first - 1, cur.second - 1, h, w);
	}
}

int solve(vector<vector<bool>>& map, int h, int w)
{
	int count = 0;

	int s_h = 0;
	int s_w = 0;

	while (s_h < h && s_w < w) {
		if (map[s_h][s_w]) {
			solve_one(map, h, w, s_h, s_w);
			count++;
		}

		s_w++;
		if (s_w == w) {
			s_h++;
			s_w = 0;
		}
	}

	return count;
}

int main()
{
	while (true) {
		int h, w; cin >> w >> h;
		if (h == 0 && w == 0) return 0;

		vector<vector<bool>> map(h, vector<bool>(w));
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				int s; cin >> s;
				if (s == 0) map[i][j] = false;
				if (s == 1) map[i][j] = true;
			}
		}

		int count = solve(map, h, w);
		cout << count << endl;
	}

	return 0;
}

C++: #include <bits/stdc++.h>
#define REP(i, n) for(int i = 0; i < (n); i++)
#define REP1(i, n) for(int i = 1; i <= (n); i++)
#define REPD(i,a,b) for (int i=(a);i<(b);i++)
#define ALL(v) (v).begin(), (v).end()
using namespace std;
typedef long long ll;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef set<int> si;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef pair<int, int> pi;
typedef queue<pi> qpi;
typedef pair<ll, ll> pll;
typedef queue<pll> qpll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
const int mod = 1000000007;
const int INF = 1001001001;
// 小数点　<< fixed << setprecision(0) <<
// sort降順　sort(ALL(),greater<int>());
// 円周率　M_PI
// 文字判定　isupper islower
// 順列　do {} while(next_permutation(ALL(X)));
// 最大値　LLONG_MAX
// a内でx以上　auto iter = lower_bound(ALL(a), x);
// a内でxより大きい　auto iter = upper_bound(ALL(a), x);
int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
int dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};
struct edge {
    int from; //出発点
    int to;   //到達点
    int cost; //移動コスト
};
typedef struct edge se;
typedef vector<edge> ve;
unsigned euclidean_gcd(unsigned a, unsigned b) {
  if(a < b) return euclidean_gcd(b, a);
  unsigned r;
  while ((r=a%b)) {
    a = b;
    b = r;
  }
  return b;
}

void dfs(vvi g,int v, int &time,vb &seen,vi &first_time,vi &last_time) {
  first_time[v]=++time;
  seen[v]=true;
  for(auto next_v:g[v]) {
    if(seen[next_v]) continue;
    dfs(g,next_v,time,seen,first_time,last_time);
  }
  last_time[v]=++time;
}
void xdfs(vvi c,int h, int w,int y,int x,vvb &seen) {
  if(seen[y][x]) return;
  seen[y][x]=true;
  REP(i,8) {
    int cx=x+dx[i];
    int cy=y+dy[i];
    if(cx<0||cy<0||cx>=w||cy>=h) continue;
    if(c[cy][cx]!=1) continue;
    xdfs(c,h,w,cy,cx,seen);
  }
}


int main() {
  while (1)
  {
    int w,h;
    cin >> w >> h;
    if(w==0&&h==0) break;
    vvi c(h,vi(w,0));
    REP(i,h) {
      REP(j,w) {
        cin >> c[i][j];
      }
    }
    vvb seen(h,vb(w,false));
    int ans=0;
    REP(i,h) {
      REP(j,w) {
        if(c[i][j]!=1) continue;
        if(seen[i][j]) continue;
        xdfs(c,h,w,i,j,seen);
        ans++;
      }
    }
    cout << ans << endl;
  }
  
  return 0;
}