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>
#include <numeric>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <string>
#include <cstring>
#include <queue>
#define myfor(i,N) for(i=0;i<N;i++)
#define myforFL(i,f,l) for(i=f;i<l;i++)
#define myforInv(i,N) for(i=N;i>=0;i--)
#define myforFLInv(i,f,l) for(i=f;i>l;i--)

using namespace std;
int dx[]={1,-1,0,0,1,-1,1,-1},dy[]={0,0,1,-1,1,-1,-1,1};
int w,h;
vector<vector<int> >c(50, vector<int>(50));
vector<vector<bool> >done(50, vector<bool>(50,false));

int dfs(int x, int y){
	int i;
	if(c[x][y] == 0)return 0;
	
	myfor(i,8){
		if(x+dx[i]>=0&&x+dx[i]<w && y+dy[i]>= 0 && y+dy[i] < h )if(!done[x+dx[i]][y+dy[i]]&& c[x+dx[i]][y+dy[i]] == 1){
			done[x+dx[i]][y+dy[i]] = true;
			dfs(x+dx[i],y+dy[i]);
		}
	}
	done[x][y] = true;
	return 1;
}
int mainloop(int win, int hin){
	int i,j,count=0;
	w = win,h=hin;
	
	myfor(i,w)myfor(j,h)cin >> c[i][j];
	myfor(i,w)myfor(j,h){
		if(!done[i][j])count+= dfs(i,j);
	}
	return count;
}

int main(){
	int win=1,hin=1,i;
	vector<int> ans;
	while(win != 0 && hin != 0){
		cin >> win >> hin;
		int cnt=0;
		if(win != 0 && hin != 0){
			done.assign(50,vector<bool>(50,false));
			ans.push_back(mainloop(hin,win));
		}
	}
	myfor(i,ans.size())cout << ans[i] << endl;
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <stack>
#include <utility>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define FST first
#define SEC second

typedef pair <int,int> pxy;

int dfs(int map[][50],int w,int h){
  int dd[10]={0, 1, 1, 1, 0, -1, -1, -1, 0, 1};
  stack <pxy> s;
  int num=0;
  rep(y,h){
    rep(x,w){
      if(map[x][y]==1){
	s.push(pxy(x,y));
	while(!s.empty()){
	  int cx=s.top().FST,cy=s.top().SEC;
	  s.pop();
	  map[cx][cy]=0;
	  rep(r,8){
	    int nx=cx+dd[r],ny=cy+dd[r+2];
	    if(nx<0||w<=nx||ny<0||h<=ny||map[nx][ny]==0) continue;
	    s.push(pxy(nx,ny));
	  }
	}
	num++;
      }
    }
  }
  return num;
}

int main() {
  for(;;){
    int w,h,x,y;
    scanf("%d %d",&w,&h);
    int map[50][50];
    if(w==0&&h==0) break;
    rep(i,h){
      rep(j,w){
	cin >> map[j][i];
      }
    }
    cout << dfs(map,w,h) << endl;
  } 
}

C++: #include <bits/stdc++.h>
using namespace std;

int main() {
    int n, m;
    int dx[] = {1, 0, -1, 0, 1, 1, -1, -1};
    int dy[] = {0, 1, 0, -1, 1, -1, 1, -1};
    while (cin >> m >> n, n || m) {
        vector<vector<int>> v(n, vector<int>(m));
        for (auto& i : v) for (auto& j : i) cin >> j;

        int count = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (v[i][j] == 0) continue;
                count++;
                queue<pair<int,int>> que;
                que.push(make_pair(i, j));

                while (que.size()) {
                    auto p = que.front();
                    que.pop();
                    int x = p.first;
                    int y = p.second;

                    if (v[x][y] == 0) continue;

                    v[x][y] = 0;

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

                        if (0 <= nx && nx < n && 0 <= ny && ny < m && v[nx][ny] == 1) {
                            que.push(make_pair(nx, ny));
                        }
                    }
                }
            }
        }

        cout << count << endl;
    }

    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <utility>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <limits>
#include <cmath>
#include <cassert>
#include <queue>

using namespace std;
using ll = long long;

const int INF = 1<<30;
const int MOD = (int)1e9 + 7;
const int MAX_N = (int)1e5 + 5;
const int dy[] = {1, 0, -1, 0, 1, 1, -1, -1};
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1};
#define debug(x) cout << #x << ": " << x << endl

int W, H;

void bfs(int y, int x, const vector<vector<int>> &table, vector<vector<int>> &flag)
{
    using P = pair<int, int>;
    queue<P> que;
    que.push(P(y, x));
    flag[y][x] = 0;
    while(que.size())
    {
        P p = que.front(); que.pop();
        for(int i = 0; i < 8; i++)
        {
            int ny = p.first + dy[i];
            int nx = p.second + dx[i];
            if(ny < 0 or nx < 0 or ny >= H or nx >= W) continue;
            if(table[ny][nx] == 0 or not flag[ny][nx]) continue;
            flag[ny][nx] = 0;
            que.push(P(ny, nx));
        }
    }
}

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    while(cin >> W >> H, W or H)
    {
        vector<vector<int>> table(H, vector<int>(W));
        for(int i = 0; i < H; i++)
        {
            for(int j = 0; j < W; j++) cin >> table[i][j];
        }
        vector<vector<int>> flag = table;
        int ans = 0;
        for(int i = 0; i < H; i++)
        {
            for(int j = 0; j < W; j++)
            {
                if(not flag[i][j]) continue;
                ans++;
                bfs(i, j, table, flag);
            }
        }
        cout << ans << endl;
    }
    return 0;
}