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 <cmath>
#include <vector>
#include <string>
#include <map>
#include <algorithm>
#include <tuple>
#include <set>
#include <stack>
#include <queue>
#define REP(i, n) for(LL i = 0;i < n;i++)
#define REPR(i, n) for(LL i = n;i >= 0;i--)
#define FOR(i, m, n) for(LL i = m;i < n;i++)
#define FORR(i, m, n) for(LL i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define pb(a) push_back(a)
#define all(x) (x).begin(),(x).end()

#define INF 999999999
#define MOD 1000000007
using namespace std;
typedef long long LL;
//typedef LL int;
typedef pair<int, int> P;
typedef pair<LL, LL> LP;
typedef pair<int, P> PP;
typedef pair<LL, LP> LPP;
int dy[]={0, 0, 1, -1, 0};
int dx[]={1, -1, 0, 0, 0};

int main(){
    int w, h;
    while(cin >> w >> h, w + h){
        int c[51][51];
        REP(i, h){
            REP(j, w){
            cin >> c[i][j];
            }
        }

        int ans = 0;

        REP(i, h){
            REP(j, w){
                if(c[i][j] == 0) continue;
                else if(c[i][j] == 1){
                    queue<int> que;
                    que.push(i); que.push(j);
                    c[i][j] = 0;
                    while(!que.empty()){
                        int x, y;
                        y = que.front(); que.pop();
                        x = que.front(); que.pop();
                        
                        //??????
                        if(y-1 >= 0 && y-1 < h && x-1 >= 0 && x-1 < w && c[y-1][x-1] == 1){
                            que.push(y-1); que.push(x-1);
                            c[y-1][x-1] = 0;
                        }
                        //???
                        if(y-1 >= 0 && y-1 < h && x >= 0 && x < w && c[y-1][x] == 1){
                            que.push(y-1); que.push(x);
                            c[y-1][x] = 0;
                        }
                        //??????
                        if(y-1 >= 0 && y-1 < h && x+1 >= 0 && x+1 < w && c[y-1][x+1] == 1){
                            que.push(y-1); que.push(x+1);
                            c[y-1][x+1] = 0;
                        }
                        //???
                        if(y >= 0 && y < h && x-1 >= 0 && x-1 < w && c[y][x-1] == 1){
                            que.push(y); que.push(x-1);
                            c[y][x-1] = 0;
                        }
                        //???
                        if(y >= 0 && y < h && x+1 >= 0 && x+1 < w && c[y][x+1] == 1){
                            que.push(y); que.push(x+1);
                            c[y][x+1] = 0;
                        }
                        //??????
                        if(y+1 >= 0 && y+1 < h && x-1 >= 0 && x-1 < w && c[y+1][x-1] == 1){
                            que.push(y+1); que.push(x-1);
                            c[y+1][x-1] = 0;
                        }
                        //???
                        if(y+1 >= 0 && y+1 < h && x >= 0 && x < w && c[y+1][x] == 1){
                            que.push(y+1); que.push(x);
                            c[y+1][x] = 0;
                        }
                        //??????
                        if(y+1 >= 0 && y+1 < h && x+1 >= 0 && x+1 < w && c[y+1][x+1] == 1){
                            que.push(y+1); que.push(x+1);
                            c[y+1][x+1] = 0;
                        }
                    }
                    ans++;
                }
            }
        }

        cout << ans << endl;
    }
}

C++: #include <bits/stdc++.h>

using namespace std;

typedef pair<int,int> P;

int c[1000][1000];//0??????
int h,w;

int dx[8]={1,1,0,-1,-1,-1,0,1},dy[8]={0,1,1,1,0,-1,-1,-1};

void bfs(int i,int j){
    queue<P> q;
    q.push(P(i,j));
    while(!q.empty()){
        int x=q.front().first,y=q.front().second;
        q.pop();
        c[x][y]=0;
        for(int i=0;i<8;i++){
            int nx=x+dx[i],ny=y+dy[i];
            if(0<=nx&&nx<h&&0<=ny&&ny<w&&c[nx][ny]==1){
                q.push(P(nx,ny));
            }
        }
    }
}

int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);

  while(true){
      cin>>w>>h;
      if(w==0&&h==0) break;
      for(int i=0;i<h;i++)for(int j=0;j<w;j++){
          cin>>c[i][j];
      }
      int res=0;
      for(int i=0;i<h;i++)for(int j=0;j<w;j++){
          if(c[i][j]==1){
              bfs(i,j);
              res++;
          }
      }
      cout<<res<<endl;
  }
}

C++: #include <iostream>

#define inRange(x, y, w, h) (0 <= x && x < w && 0 <= y && y < h)

using namespace std;

int w, h;
int fd[50][50];

int dx[] = { 0, 0, -1, 1, -1, 1, -1, 1 };
int dy[] = { -1, 1, 0, 0, -1, -1, 1, 1 };

void dfs( int x, int y )
{
	fd[y][x] = 0;
	for(int i=0; i < 8; ++i) {
		int mx = x + dx[i];
		int my = y + dy[i];
		if(inRange(mx, my, w, h) && fd[my][mx])
			dfs(mx, my);
	}
}

int main( void )
{
	while(cin >> w >> h, w | h) {
		for(int y=0; y < h; ++y)
			for(int x=0; x < w; ++x)
				cin >> fd[y][x];
		int count = 0;
		for(int y=0; y < h; ++y)
			for(int x=0; x < w; ++x)
				if(fd[y][x]) {
					++count;
					dfs(x, y);
				}
		cout << count << endl;
	}
	return 0;
}

C++: #include <iostream>
using namespace std;

bool field[100][100];

int w, h;

int dx[8] = {-1, 0, 1, 0, -1, -1, 1, 1};
int dy[8] = {0, -1, 0, 1, -1, 1, -1, 1};

void bfs(int x, int y) {
  field[y][x] = false;
  for(int i = 0; i < 8; i++) {
    int tx = x+dx[i], ty = y+dy[i];

    if(0 <= tx && tx < w && 0 <= ty && ty < h && field[ty][tx]) {
      bfs(tx, ty);
    }
  }
}

int main() {
  while(cin >> w >> h, w+h) {
    for(int i = 0; i < h; i++) {
      for(int j = 0; j < w; j++) {
        cin >> field[i][j];
      }
    }

    int ans = 0;
    for(int i = 0; i < h; i++) {
      for(int j = 0; j < w; j++) {
        if(field[i][j]) {
          ans++;
          bfs(j, i);
          /*for(int k = 0; k < h; k++) {
            for(int l = 0; l < w; l++) {
              cout<< field[k][l] << ' ';
            }
            cout<< endl;
          }
          cout << endl;*/
        }
      }
    }
    cout << ans << endl;
  }
}