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 <algorithm>
#include <vector>
#include <iomanip>
#include <map>
#include <queue>
#include <set>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using namespace std;

template<class T>
constexpr T INF = ::numeric_limits<T>::max() / 32 * 15 + 208;

class UnionFind {
    int n;
public:
    vector<int> uni;
    explicit UnionFind(int n) : uni(static_cast<u32>(n), -1) , n(n){};

    int root(int a){
        if (uni[a] < 0) return a;
        else return (uni[a] = root(uni[a]));
    }

    bool unite(int a, int b) {
        a = root(a);
        b = root(b);
        if(a == b) return false;
        if(uni[a] > uni[b]) swap(a, b);
        uni[a] += uni[b];
        uni[b] = a;
        return true;
    }
};

int main() {
    int w, h;
    while(cin >> w >> h, w|h){
        UnionFind uf(h*w);
        vector<vector<int>> v(h+2, vector<int> (w+2, 0));
        for (int i = 0; i < h; ++i) {
            for (int j = 0; j < w; ++j) {
                int x;
                cin >> x;
                v[i+1][j+1] = x;
            }
        }
        auto f = [&](int p, int q){ return p*w+q; };
        int dy[] {1, 1, 1, 0, 0, -1, -1, -1},
            dx[] {-1, 0, 1, -1, 1, -1, 0, 1};
        for (int i = 0; i < h; ++i) {
            for (int j = 0; j < w; ++j) {
                if(v[i+1][j+1] == 0) continue;
                for (int k = 0; k < 8; ++k) {
                    if(v[i+dy[k]+1][j+dx[k]+1]){
                        uf.unite(f(i, j), f(i+dy[k], j+dx[k]));
                    }
                }
            }
        }
        set<int> s;
        for (int i = 0; i < h; ++i) {
            for (int j = 0; j < w; ++j) {
                if(v[i+1][j+1]) s.insert(uf.root(f(i, j)));
            }
        }
        cout << s.size() << "\n";
    }
    return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int W,H;
vector<vector<int> > field;

void dfs(int h, int w){
    field[h][w] = 0;
    for(int i = -1; i <= 1; i++){
        for(int j = -1; j <= 1; j++){
            int nh = h + i;
            int nw = w + j;
            if(nh < 0 || nh >= H || nw < 0 || nw >= W) continue;
            if(field[nh][nw]==0) continue;
            dfs(nh,nw);
        }
    }
}

int main(){
    while(cin >> W >> H){
        if(W==0 || H==0) break;
        field.assign(H, vector<int>(W,0));
        for(int i = 0; i < H; i++){
            for(int j = 0; j < W; j++){
                cin >> field[i][j];
            }
        }
        int count = 0;
        for(int i = 0; i < H; i++){
            for(int j = 0; j < W; j++){
                if(field[i][j]==0)continue;
                dfs(i,j);
                count++;
            }
        }
        cout << count << endl;
    }
    return 0;
}

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

using namespace std;

#define rep(i, n) for (int i = 0; i < n; i++)
#define vec vector

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

int dp[55][55];
int c[55][55];

int check(int x, int y)
{
	if (dp[x][y]) return 0;
	if (c[x][y] == 0) return 0;
	dp[x][y] = 1;
	
	rep(i, 8) {
		int xx = x + dx[i];
		int yy = y + dy[i];
		int take = check(xx, yy);
	}
	return 1;
}

int main(void)
{
	while(1) {
		int w, h;
		cin >> w >> h;
		if (w == 0) break;
		rep(i, 55) rep(j, 55) c[i + 1][j + 1] = 0;
		rep(i, h) rep (j, w) cin >> c[i + 1][j + 1];
		rep(i, 55) rep(j, 55) dp[i][j] = 0;
		rep(i, 55) {
			dp[0][i] = 1;
			dp[i][0] = 1;
			dp[h + 1][i] = 1;
			dp[i][w + 1] = 1;
		}

		int ans = 0;
		rep(i, h) rep(j, w) if (c[i + 1][j + 1]) ans += check(i + 1, j + 1);
		cout << ans << endl;
	}
	return 0;
}

C++: #include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<cassert>
#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<queue>
#include<set>
#include<map>
#include<utility>
#include<numeric>
#include<algorithm>
#include<bitset>
#include<complex>

using namespace std;

typedef long long Int;
typedef vector<int> vint;
typedef pair<int,int> pint;
#define mp make_pair

template<class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cout << *i << " "; cout << endl; }
template<class T> void chmin(T &t, T f) { if (t > f) t = f; }
template<class T> void chmax(T &t, T f) { if (t < f) t = f; }
int in() { int x; scanf("%d", &x); return x; }

int sea[60][60];
int w,h;

void f(int x,int y){
//cout<<x<<" "<<y<<endl;
	int i,j;
/*for(i=0;i<h;i++){
	for(j=0;j<w;j++){
		cout<<sea[i][j]<<" ";
	}
	cout<<endl;
}*/
	sea[y][x]=0;
	for(i=-1;i<2;i++){
		for(j=-1;j<2;j++){
			if(y+i<0||h<=y+i||x+j<0||w<=x+j)continue;
			if(sea[y+i][x+j]==1)f(x+j,y+i);
		}
	}
}

int main() {
	while(w=in(),h=in()){
		int i,j;
		for(i=0;i<h;i++){
			for(j=0;j<w;j++){
				cin>>sea[i][j];
			}
		}
		/*for(i=0;i<h;i++){
			for(j=0;j<w;j++){
				cout<<sea[i][j]<<" ";
			}
			cout<<endl;
		}*/
		int res=0;
		for(i=0;i<h;i++){
			for(j=0;j<w;j++){
				if(sea[i][j]==1){
					f(j,i);
					res++;
				}
			}
		}
		cout<<res<<endl;
	}
	return 0;
}