Go: // AOJ 1160: How Many Islands? http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=1160

package main

import (
	"bufio"
	"container/list"
	"fmt"
	"os"
	"strconv"
)

var SEA = 0
var LAND = 1

func nextInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

func discoverIslands(M, V [][]int, H, W int) int {
	// 島を探す
	queue := list.New()
	islands := 0
	for i := 1; i <= H; i++ {
		for j := 1; j <= W; j++ {
			// 訪問済みの土地ならスキップ
			if V[i][j] == 1 {
				continue
			}

			// 訪問中の土地が海なら訪問済みにしてスキップ
			if M[i][j] == SEA {
				V[i][j] = 1
				continue
			}

			// 未訪問の陸地が見つかったので
			// 島の数を1つ増やし、この陸地から辿れる陸地を訪問していく
			islands++
			queue.PushBack([]int{i, j})

			for queue.Len() > 0 {
				cur := queue.Remove(queue.Front()).([]int)
				h, w := cur[0], cur[1]
				if V[h][w] == 1 {
					continue
				}
				V[h][w] = 1

				// 全方向に未訪問の陸地がないか探索
				for v := -1; v <= 1; v++ {
					for l := -1; l <= 1; l++ {
						dh := h + v
						dw := w + l
						if M[dh][dw] == LAND && V[dh][dw] == 0 {
							queue.PushBack([]int{dh, dw})
						}
					}
				}
				/*
					if M[h-1][w] == LAND {
						queue.PushBack([]int{h - 1, w})
					}
					if M[h-1][w+1] == LAND {
						queue.PushBack([]int{h - 1, w + 1})
					}
					if M[h][w+1] == LAND {
						queue.PushBack([]int{h, w + 1})
					}
					if M[h+1][w+1] == LAND {
						queue.PushBack([]int{h + 1, w + 1})
					}
					if M[h+1][w] == LAND {
						queue.PushBack([]int{h + 1, w})
					}
					if M[h+1][w-1] == LAND {
						queue.PushBack([]int{h + 1, w - 1})
					}
					if M[h][w-1] == LAND {
						queue.PushBack([]int{h, w - 1})
					}
					if M[h-1][w-1] == LAND {
						queue.PushBack([]int{h - 1, w - 1})
					}
				*/
			}
		}
	}
	return islands
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	for {
		W, H := nextInt(sc), nextInt(sc)

		if W == 0 && H == 0 {
			break
		}
		// Initialize map and visted list
		M := make([][]int, H+2)
		V := make([][]int, H+2)
		for i := 0; i < H+2; i++ {
			M[i] = make([]int, W+2)
			V[i] = make([]int, W+2)
		}
		for i := 1; i <= H; i++ {
			for j := 1; j <= W; j++ {
				M[i][j] = nextInt(sc)
			}
		}

		islands := discoverIslands(M, V, H, W)

		fmt.Println(islands)
	}
}

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

int w,h;
vector<vector<int> > m;
int dx[] = {0, 0,1,-1,1, 1,-1,-1};
int dy[] = {1,-1,0, 0,1,-1, 1,-1};

void dfs(int y, int x){
  m[y][x] = 0;
  
  for(int i=0; i<8; i++){
    int nx = x + dx[i];    
    int ny = y + dy[i];
    if(nx >= w || nx < 0 || ny >= h || ny < 0) continue;
    if(m[ny][nx] == 1)
      dfs(ny,nx);
  }

}



int main(){

  while(1){
    cin >> w >> h;
    if(!w and !h) break;

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

    int ans = 0;
    for(int i=0; i<h; i++){
      for(int j=0; j<w; j++){
	if(m[i][j] == 1){
	  dfs(i,j);
	  ans++;
	}
      }
    }
    cout << ans << endl;
  }

}

C++: #include<iostream>
using namespace std;
int w,h,i,j;
int map[51][51];

void rec(int i,int j){
  if(i<1 || i>h || j<1 || j>w){
    return;
  }
  
  if(map[i][j]==0)return;
  map[i][j]=0;
  rec(i+1,j);
  rec(i-1,j);
  rec(i,j-1);
  rec(i,j+1);
  rec(i-1,j-1);
  rec(i-1,j+1);
  rec(i+1,j-1);
  rec(i+1,j+1);
}
int main(){
  
  
  while(1){
    cin >> w >> h;
    if(w==0 && h==0)break;
    
    for(i=1;i<=h;i++){
      for(j=1;j<=w;j++){
	cin >> map[i][j];
	
      }
    }
    int count=0;
    for(int k=1;k<=h;k++){
      for(int l=1;l<=w;l++){
	if(map[k][l]==1){
	  count++;
	  rec(k,l);
	}
      }
    }
    cout << count << endl;
  }
  
  return 0;
}

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

using namespace std;

#define llong long long 
int w,h;
int sum;
int area[50][50];
int nw[8] = {0, 1, 1, 1, 0, -1, -1, -1};
int nh[8] = {1, 1, 0, -1, -1, -1, 0, 1};

void solve(int h, int w){
	if(area[h][w] == 0)return;
	area[h][w] == 0;
	for(int i = 0; i < 8; i++){
		int sh = h + nh[i];
		int sw = w + nw[i];
		if(sh < 0 || sw < 0 || sh >= h || sw >= w) continue;
		solve(sh, sw);
	}
	return;
}

int main(){

	while(cin >> w >> h, w){
		sum = 0;
		fill_n(*area, 50 * 50, 0);
		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){
					sum++;
					solve(i, j);
				}
			}
		}

		cout << sum << endl;
	return 0;
}

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

using namespace std;

#define REP(i, n) for (int i=0; i<(n); ++i)
#define RREP(i, n) for (int i=(int)(n)-1; i>=0; --i)
#define FOR(i, a, n) for (int i=(a); i<(n); ++i)
#define RFOR(i, a, n) for (int i=(int)(n)-1; i>=(a); --i)

#define SZ(x) ((int)(x).size())
#define all(x) begin(x),end(x)

#define dump(x) cerr<<#x<<" = "<<(x)<<endl
#define debug(x) cerr<<#x<<" = "<<(x)<<" (L"<<__LINE__<<")"<<endl;

template<class T>
ostream &operator<<(ostream &os, const vector <T> &v) {
    os << "[";
    REP(i, SZ(v)) {
        if (i) os << ", ";
        os << v[i];
    }
    return os << "]";
}

template<class T, class U>
ostream &operator<<(ostream &os, const pair <T, U> &p) {
    return os << "(" << p.first << " " << p.second << ")";
}

template<class T>
bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmin(T &a, const T &b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using vvi = vector<vi>;
using vvll = vector<vll>;

const ll MOD = 1e9 + 7;
const int INF = INT_MAX / 2;
const ll LINF = LLONG_MAX / 2;
const ld EPS = 1e-9;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);

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

    for (;;) {
        int w, h; cin >> w >> h;
        if (w == 0) break;

        vvi s(h, vi(w));
        REP(i, h) REP(j, w) cin >> s[i][j];

        vvi vis(h, vi(w));
        function<void(int,int)> dfs = [&](int i, int j) {
            vis[i][j] = 1;
            REP(k, 8) {
                int y = i + dy[k], x = j + dx[k];
                if (y < 0 or x < 0 or y >= h or x >= w) continue;
                if (s[y][x] == 0) continue;
                if (vis[y][x]) continue;
                dfs(y, x);
            }
        };

        int ans = 0;
        REP(i, h) REP(j, w) if (s[i][j] == 1 and !vis[i][j]) {
            ++ans;
            dfs(i, j);
        }
        cout << ans << endl;
    }

    return 0;
}