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 <string.h>

using namespace std;

int c[50][50];
bool visit[50][50];
const int dx[8] = {1,0,-1,0,1,1,-1,-1};
const int dy[8] = {0,1,0,-1,1,-1,1,-1};
int w,h;

void dfs(int x,int y)
{
	int tmp_x,tmp_y;
	for (int i=0;i<8;++i)
	{
		tmp_x = x + dx[i];
		tmp_y = y + dy[i];
		
		if (0<=tmp_x&&tmp_x<w&&0<=tmp_y&&tmp_y<h&&!visit[tmp_y][tmp_x]&&c[tmp_y][tmp_x] == 1)
		{
			visit[tmp_y][tmp_x] = true;
			dfs(tmp_x,tmp_y);
		}
	}
	return;
}

int main()
{

	int count;
	cin >> w >> h;
	
	while (w+h >0)
	{
		count = 0;
		memset(visit,0,sizeof(visit));
		for (int i=0;i<h;++i)
		{
			for (int j=0;j<w;++j)
			{
				cin >> c[i][j];
			}
		}
		
		for (int i=0;i<h;++i)
		{
			for (int j=0;j<w;++j)
			{
				if (!visit[i][j]&&c[i][j]==1)
				{
					++count;
					dfs(j,i);
				}
			}
		}
		
		cout << count <<endl;
		
		cin >> w >> h;
	}
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll,ll> pl;
typedef vector<pl> vp;
#define fore(i,a,b) for(ll i=(a);i<=(b);++i)
#define rep(i,n) fore(i,0,(n)-1)
#define rfore(i,a,b) for(ll i=(b);i>=(a);--i)
#define rrep(i,n) rfore(i,0,(n)-1)
#define all(x) (x).begin(),(x).end()
const ll INF=1001001001;
const ll LINF=1001001001001001001;
const ll D4[]={0,1,0,-1,0};
const ll D8[]={0,1,1,0,-1,-1,1,-1,0};
template<class T>
bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>
bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
template<class T>
ll sum(const T& a){return accumulate(all(a),0LL);}

ll w,h;
ll c[55][55];
bool u[55][55];
void dfs(ll y,ll x){
    u[y][x]=1;
    rep(i,8){
        ll ny=y+D8[i];
        ll nx=x+D8[i+1];
        if(ny<0||h<=ny||nx<0||w<=nx||!c[ny][nx]||u[ny][nx])continue;
        dfs(ny,nx);
    }
}
void solve(){
    while(1){
        cin>>w>>h;
        if(w==0&&h==0)return;
        rep(i,h)rep(j,w){
            cin>>c[i][j];
            u[i][j]=0;
        }
        ll cnt=0;
        rep(i,h)rep(j,w){
            if(c[i][j]&&!u[i][j]){
                cnt++;
                dfs(i,j);
            }
        }
        cout<<cnt<<endl;
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    solve();
}