Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)
var route [][]int

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(h, w int) {
	if route[h][w] == 0 {
		return
	}

	route[h][w] = 0
	for _, x := range []int{-1, 0, 1} {
		for _, y := range []int{-1, 0, 1} {
			if route[h+x][w+y] == 0 {
				continue
			}
			dfs(h+x, w+y)
		}
	}
}

func main() {
	writer := bufio.NewWriter(os.Stdout)
	for {
		w, h := scanInt(), scanInt()
		if w == 0 && h == 0 {
			break
		}

		route = make([][]int, h+2)
		route[0] = make([]int, w+2)
		for i := 1; i <= h; i++ {
			route[i] = make([]int, w+2)
			for j := 1; j <= w; j++ {
				route[i][j] = scanInt()
			}
		}
		route[h+1] = make([]int, w+2)

		total := 0
		for i := 1; i <= h; i++ {
			for j := 1; j <= w; j++ {
				if route[i][j] == 1 {
					total++
					dfs(i, j)
				}
			}
		}
		fmt.Fprintln(writer, total)
	}
	writer.Flush()
}

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

// macros
#define ll long long int
#define pb emplace_back
#define mk make_pair
#define pq priority_queue
#define FOR(i, a, b) for(int i=(a);i<(b);++i)
#define rep(i, n) FOR(i, 0, n)
#define rrep(i, n) for(int i=((int)(n)-1);i>=0;i--)
#define irep(itr, st) for(auto itr = (st).begin(); itr != (st).end(); ++itr)
#define irrep(itr, st) for(auto itr = (st).rbegin(); itr != (st).rend(); ++itr)
#define vrep(v, i) for(int i = 0; i < (v).size(); i++)
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define FI first
#define SE second
#define dump(a, n) for(int i = 0; i < n; i++)cout << a[i] << "\n "[i + 1 != n];
#define dump2(a, n, m) for(int i = 0; i < n; i++)for(int j = 0; j < m; j++)cout << a[i][j] << "\n "[j + 1 != m];
#define bit(n) (1LL<<(n))
#define INT(n) int n; cin >> n;
#define LL(n) ll n; cin >> n;
#define DOUBLE(n) double n; cin >> n;
using namespace std;

//  types
typedef pair<int, int> P;
typedef pair<ll, int> Pl;
typedef pair<ll, ll> Pll;
typedef pair<double, double> Pd;
typedef complex<double> cd;
 
// constants
const int inf = 1e9;
const ll linf = 1LL << 50;
const double EPS = 1e-10;
const int mod = 1e9 + 7;
const int dx[8] = {-1, 0, 1, 0, -1, -1, 1, 1};
const int dy[8] = {0, -1, 0, 1, -1, 1, -1, 1};

// solve
template <class T>bool chmax(T &a, const T &b){if(a < b){a = b; return 1;} return 0;}
template <class T>bool chmin(T &a, const T &b){if(a > b){a = b; return 1;} return 0;}
template <typename T> istream &operator>>(istream &is, vector<T> &vec){for(auto &v: vec)is >> v; return is;}
template <typename T> ostream &operator<<(ostream &os, const vector<T>& vec){for(int i = 0; i < vec.size(); i++){ os << vec[i]; if(i + 1 != vec.size())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_set<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T> ostream &operator<<(ostream &os, const unordered_multiset<T>& st){for(auto itr = st.begin(); itr != st.end(); ++itr){ os << *itr; auto titr = itr; if(++titr != st.end())os << " ";} return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &p){os << p.first << " " << p.second; return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}
template <typename T1, typename T2> ostream &operator<<(ostream &os, const unordered_map<T1, T2> &mp){for(auto itr = mp.begin(); itr != mp.end(); ++itr){ os << itr->first << ":" << itr->second; auto titr = itr; if(++titr != mp.end())os << " "; } return os;}

int w, h;
int a[51][51];
bool vis[51][51];

void dfs(int i, int j){
  vis[i][j] = true;
  rep(k, 8){
    int nx = i + dx[k];
    int ny = j + dy[k];
    if(nx >= 0 && nx < h && ny >= 0 && ny < w && !vis[nx][ny]){
      if(a[nx][ny] == 1)dfs(nx, ny);
    }
  }
}

int main(int argc, char const* argv[])
{
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout << fixed << setprecision(20);
  cin >> w >> h;
  while(w > 0 || h > 0){
    rep(i, h)rep(j, w)cin >> a[i][j];
    rep(i, h)rep(j, w)vis[i][j] = false;
    int res = 0;
    rep(i, h){
      rep(j, w){
        if(!vis[i][j] && a[i][j] == 1){
          res++;
          dfs(i, j);
        }
      }
    }
    cout << res << endl;
    cin >> w >> h;
  }
  return 0;
}

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

int c[50][50];
bool visited[50][50] = {false};
int w, h;


void search(int x, int y){
    if(x < 0 || x >= w || y < 0 || y >= h || c[y][x] == 0){
        return;
    }
    if(visited[y][x] == true){
        return;
    }

    visited[y][x] = true;

    search(x-1, y);
    search(x+1, y);
    search(x, y-1);
    search(x, y+1);
    search(x+1, y+1);
    search(x+1, y-1);
    search(x-1, y+1);
    search(x-1, y-1);
}

void init(){
    for(int y = 0; y < 50; y++){
        for(int x = 0; x < 50; x++){
            visited[y][x] = false;
        }
    }
}


int main(){
    int count;
    int n = 0;
    vector<int> ans;

    while(1){
        cin >> w >> h;

        if(w == 0 and h == 0){
            break;
        }

        n++;
        count = 0;

        for(int y = 0; y < h; y++){
            for(int x = 0; x < w; x++){
                cin >> c[y][x];
            }
        }

        for(int y = 0; y < h; y++){
            for(int x = 0; x < w; x++){
                if(c[y][x] == 1 and visited[y][x] == false){
                    search(x, y);
                    count++;
                }
            }
        }

        ans.push_back(count);
        
        init();
    }

    for(int j = 0; j < n; j++){
        printf("%d\n", ans[j]);
    }

    return 0;

}

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

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

int map[51][51];
int w, h;

//void printmap() {
//	for (int i = 0 ; i < h; i++) {
//		for (int j = 0; j < w; j++)
//			cout << map[i][j] << " ";
//		cout << endl;
//	}
//}

void oneIsland(int x, int y) {
	for (int i = 0; i < 8; i++) {
		int nextX = x + dx[i];
		int nextY = y + dy[i];
		if (x < 0 || w <= x) continue;
		if (y < 0 || w <= y) continue;
		if (map[nextY][nextX] == 0) continue;
		map[nextY][nextX] = 0;
		oneIsland(nextX, nextY);
	}
}

int main() {
	while (1) {
		cin >> w >> h;
		if (w == 0 && h == 0) break;
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				cin >> map[i][j];
			}
		}
		
		int count = 0;
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				if (map[i][j] == 1) {
					map[i][j] = 0;
					oneIsland(j, i);
					//printmap();
					count++;
				}
			}
		}
		cout << count <<endl;
	}
	return 0;
}