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>
using namespace std;

int w,h;
int c[100][100];
int dy[] = {-1,-1,0,1,1,1,0,-1}, dx[] = {0,1,1,1,0,-1,-1,-1};

void rec(int y,int x){
  if(y<0 || x<0 || y>=h || x>=w)return;
  if(c[y][x]==0)return;
  c[y][x] = 0;
 
  for(int i=0;i<8;i++){
    rec(y+dy[i],x+dx[i]);
  }
}
 
int main(){
  while(cin >> w >> h,w){
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++)cin >> c[i][j];
    }

    int cnt = 0;
    for(int i=0;i<h;i++){
      for(int j=0;j<w;j++){
	if(c[i][j]){
	  rec(i,j); cnt++;
	}
      }
    }

    cout << cnt << endl;
  }
}

C++: #include <bits/stdc++.h>
#define be(v) (v).begin(),(v).end()
#define pb(q) push_back(q)
typedef long long ll;
using namespace std;
const ll mod=1000000007;
#define doublecout(a) cout<<fixed<<setprecision(10)<<a<<endl;
int h,w,a[50][50];
int dy[8]={-1,-1,-1,0,0,1,1,1},dx[8]={-1,0,1,-1,1,-1,0,1};
ll uni[2500];
ll root(ll u){
    if(uni[u]<0)return u;
    return uni[u]=root(uni[u]);
}

void connect(int a,int b){
    a=root(a);
    b=root(b);
    if(a==b)return;
    if(uni[a]>uni[b]){
        a^=b;
        b^=a;
        a^=b;
    }
    uni[a]+=uni[b];
    uni[b]=a;
    return;
}
ll size(ll u){
    return -uni[root(u)];
}

int main() {
    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(false);
    vector<int> v;
    while(1){
    	cin>>w>>h;
    	if(!(h||w))break;
    	for(int i=0;i<h;i++){
    		for(int j=0;j<w;j++){
    			cin>>a[i][j];
    			uni[j*h+i]=(a[i][j])?-1:0;
    		}
    	}
    	for(int i=0;i<h;i++){
    		for(int j=0;j<w;j++){
    			if(a[i][j]){
    				for(int k=0;k<8;k++){
    					int x=dx[k]+j;
    					int y=dy[k]+i;
    					if(x<0||x>=w||y<0||y>=h)continue;
    					if(a[y][x]){
    						connect(j*h+i,x*h+y);
    					}
    				}
    			}
    		}
    	}
    	int ans=0;
    	for(int i=0;i<h;i++){
    		for(int j=0;j<w;j++){
    			if(a[i][j]&&uni[j*h+i]<0)ans++;
    		}
    	}
    	v.pb(ans);
    }
    for(auto& i:v)cout << i<<endl;
    return 0;
}

C++: #include<stdio.h>
#include<iostream>
#include<string>
#include<algorithm>
using namespace std;

int main(){
	int w,h;
	while(1){
		cin>>w>>h;if(w==0&&h==0)break;
	int map[55][55]={};
	int W=0;
	for(int i=0;i<h;i++)
		for(int j=0;j<w;j++)
		{int x;cin>>x;if(x==1){W++;map[i+1][j+1]=W;}}

	int MAP[55][55]={};int c=0;
	for(int i=0;i<h+1;i++)
		for(int j=0;j<w+1;j++)
		{if(map[i][j]>0){c=map[i][j];

	int G[10]={map[i-1][j-1],map[i-1][j],map[i-1][j+1],map[i][j-1],map[i][j],map[i][j+1],map[i+1][j-1],map[i+1][j],map[i+1][j+1]};
			if(map[i-1][j-1]>0&&c>map[i-1][j-1])c=map[i-1][j-1];
			if(map[i-1][j]>0&&c>map[i-1][j])c=map[i-1][j];
			if(map[i-1][j+1]>0&&c>map[i-1][j+1])c=map[i-1][j+1];
			if(map[i][j-1]>0&&c>map[i][j-1])c=map[i][j-1];
			if(map[i][j+1]>0&&c>map[i][j+1])c=map[i][j+1];
			if(map[i+1][j-1]>0&&c>map[i+1][j-1])c=map[i+1][j-1];
			if(map[i+1][j]>0&&c>map[i+1][j])c=map[i+1][j];
			if(map[i+1][j+1]>0&&c>map[i+1][j+1])c=map[i+1][j+1];
			for(int I=0;I<53;I++)
				for(int J=0;J<53;J++)
					for(int H=0;H<9;H++)
					{if(map[I][J]==G[H]&&map[I][J]>0)map[I][J]=c;}
	}
		}
	bool C[2502]={};
	for(int i=0;i<h+1;i++){//cout<<endl;
		for(int j=0;j<w+1;j++){//cout<<map[i][j]<<" ";
			if(map[i+1][j+1]>0)C[map[i+1][j+1]]=true;
		}
	}
	int R=0;
	for(int i=0;i<2501;i++)if(C[i]==true)R++;
			cout<<R<<endl;

	}
	return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
#include <bitset>
#define chmin(a, b) ((a)=min((a), (b)))
#define chmax(a, b) ((a)=max((a), (b)))
#define fs first
#define sc second
#define eb emplace_back
using namespace std;

typedef long long ll;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;

const ll MOD=1e9+7;
const ll INF=1e18;
const double pi=acos(-1);
const double eps=1e-10;

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

int main(){
    while(1){
        int w, h; cin>>w>>h;
        if(w == 0) return 0;

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

        int ans=0;
        for(int i=0; i<h; i++){
            for(int j=0; j<w; j++){
                if(c[i][j]){
                    ans++;
                    c[i][j] = 0;

                    queue<P> que;
                    que.push(P(i, j));
                    while(que.size()){
                        int cy, cx;
                        tie(cy, cx) = que.front();
                        que.pop();

                        for(int k=0; k<8; k++){
                            int ny = cy + dy[k];
                            int nx = cx + dx[k];

                            if(0 <= ny && ny < h && 0 <= nx && nx < w){
                                if(c[ny][nx]){
                                    c[ny][nx] = 0;
                                    que.push(P(ny, nx));
                                }
                            }
                        }
                    }
                }
            }
        }

        cout << ans << endl;
    }
}