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 <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int (i) = 0;(i) < (n) ; ++(i))
#define REPS(a,i,n) for(int (i) = (a) ; (i) < (n) ; ++(i))
#define REVERSE(i,n) for(int (i) = n-1;(i) >= 0 ; --i)
#define ALL(c) (c).begin() , (c).end()
#define LL long long
#define int LL
#define inf  (1LL << 60)
#define mod 1000000007
#define QUICK_CIN ios::sync_with_stdio(false); cin.tie(0);
#define lower lower_bound
#define upper upper_bound
#define ZERO(c,n) memset(&c[0],0,sizeof(int)*n)
#define ZERO2(c,n) memset(&c[0][0],0,sizeof(int)*n
#define pl(a) cout << ""#a": " << a << endl;
#ifdef _DEBUG
#define debug_io fstream cin("input.txt");ofstream cout("output.txt");
template<class T>fstream& operator>>(fstream& is, vector<T>& v)
{
	int n = v.size();
	REP(i, n) {
		is >> v[i];
	}
	return is;
}
#else
#define debug_io ;
#endif
#define debug_input debug_io
#define DOWN(T) std::greater<T>()
template<class T>istream& operator>>(istream& is, vector<T>& v)
{
	int n = v.size();
	REP(i, n) {
		is >> v[i];
	}
	return is;
}
using vs = vector<string>; using vi = vector<int>; using pii = pair<int, int>;
using psi = pair<string, int>; using vvi = vector<vi>; using pss = pair<string, string>;
using vpii = vector<pii>;
template<class T>bool valid(T x, T w) { return 0 <= x&&x < w; }
//int dx[4] = { 1, -1, 0, 0 }; int dy[4] = { 0, 0, 1, -1 };
//-----------------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------------


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

bool ed[55][55];

signed main()
{
	QUICK_CIN;
	debug_input;
	int w, h;
	while (cin >> w >> h, w + h) {
		vector<vi> tile(h, vi(w));
		REP(i, h) {
			REP(j, w) {
				cin >> tile[i][j];
			}
		}

		int ans = 0;

		REP(i, h) {
			REP(j, w) {
				if (tile[i][j] != 1) {
					continue;
				}
				REP(i, 55) {
					REP(j, 55) {
						ed[i][j] = false;
					}
				}
				queue<pii> q;
				q.push({ i,j });
				while (q.size()) {
					auto t = q.front();
					q.pop();
					auto x = t.second;
					auto y = t.first;

					if (ed[y][x]) {
						continue;
					}
					ed[y][x] = true;
					tile[y][x] = 2;

					REP(k, 8) {
						auto nx = min(w-1,max(0LL,x + dx[k]));
						auto ny = min(h-1,max(0LL,y + dy[k]));

						if (tile[ny][nx] == 1 && !ed[ny][nx]) {
							q.push({ ny,nx });
						}
					}
				}
				ans++;
			}
		}
		cout << ans << endl;

	}
}

C++: #include <iostream>

using namespace std;

int c[50][50],w,h;
int dx[]={-1,-1,-1,0,0,1,1,1};
int dy[]={-1,0,1,-1,1,-1,0,1};
void dfs(int y,int x){
  if(c[y][x]){
    c[y][x]=0;
    int i;
    for(i=0;i<8;i++){
      if(y+dy[i]>=0 || y+dy[i]<h || x+dx[i]>=0 || x+dx[i]<w)
      dfs(y+dy[i],x+dx[i]);
    }
  }
  return;
}

int main(){
  int i,j,ans;
  cin >> w >> h;
  while(1){
    ans=0;
    if(w+h==0)break;
    //for(i=0;i<50;i++)for(j=0;j<50;j++)c[i][j]=0;
    for(i=0;i<h;i++){
      for(j=0;j<w;j++)cin >> c[i][j];
    }
    for(i=0;i<h;i++){
      for(j=0;j<w;j++)if(c[i][j]){
        dfs(i,j);
        ans++;
      }
    }
    cout << ans << endl;
    cin >> w >> h;
  }
  return 0;
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<tuple>
#include<map>
#include<queue>
#include<set>
#include<stack>
#include<deque>
#include<cmath>
#include<stack>
#include<string.h>
#define rep(i,n) for(int i = 0;i<n;i++)
#define _GLIBCXX_DEBUG
using ll = long long; 
using namespace std;

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

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

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

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

char c[102][102];

int mx, my;

void dfs(int x, int y){
    if(x < 0 || y < 0 || x >= mx || y >= my){
        return;
    }
    if(c[x][y] == '0'){
        return;
    }
    c[x][y] = '0';
    dfs(x+1, y);
    dfs(x+1, y+2);
    dfs(x+1, y-2);
    dfs(x-1, y);
    dfs(x-1, y+2);
    dfs(x-1, y-2);
    dfs(x, y+2);
    dfs(x, y-2);
    return;
}

int main(){
    int W, H, cnt = 0;
    scanf("%d %d\n", &W, &H);
    while(W != 0 || H != 0){
        mx = H;
        my = W;
        for(int k = 0; k < H; k++){
            cin.getline(c[k], sizeof(c[k]));
        }
        for(int i = 0; i < H; i++){
            for(int j = 0; j < 2 * W; j++){
                if(c[i][j] == '1'){
                    cnt++;
                    dfs(i, j);
                }
            }
        }
        cout << cnt << endl;
        scanf("%d %d\n", &W, &H);
        cnt = 0;
    }
}