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<string>
#include<cstdlib>
#include<map>
#include<iomanip>
#include<sstream>
#include<vector>
#include<stack>
#include<math.h>
#include<queue>
#include<complex>
using namespace std;

struct TWO{
    long long int a,b;
};

bool cmp(TWO x,TWO y){
    if(x.a!=y.a){
        return x.a<y.a;
    }else{
        return x.b<y.b;
    }
}

int f[51][51];
int h, w;

void dfs(int y, int x) {
    if (f[y][x] == 0) return;
    f[y][x] = 0;
    int dx[3] = {-1, 0, 1};
    int dy[3] = {-1, 0, 1};
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            int nx = x + dx[i];
            int ny = y + dy[j];
            if (nx < 0 || nx == w || ny < 0 || ny == h) continue;
            if (f[ny][nx] == 1) {
                dfs(ny, nx);
            }
        }
    }
}

int main() {
    const long long int mod = 1000000007,INF=50000000000000;
    typedef pair<long long int,long long int>P;
	map<long long int, long long int>mp;
    priority_queue<P,vector<P>,greater<P> >mazuisushi;
    
    priority_queue<P>umaisushi;
	cout << fixed << setprecision(10);
    string str;
    long long int y,m,d;

    while(1){
        cin >> w >> h;
        if (w == 0) return 0;
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                cin >> f[i][j];
            }
        }
        int cnt = 0;
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                if (f[i][j] == 0) continue;
                dfs(i, j);
                cnt++; 
            }
        }
        cout << cnt << endl;
    }
}

C++: #include <iostream>
 
using namespace std;
 
int W, H;
int field[55][55];
 
void input(void){
    cin >> W;
    cin >> H;
 
    for(int i = 0;i < H;i++){
        for(int j = 0;j < W;j++){
            cin >> field[j][i];
        }
    }
}
 
void dfs(int x, int y){
    field[x][y] = 0;
 
    for(int dx = -1;dx <= 1;dx++){
        for(int dy = -1;dy <= 1;dy++){
            int nx = x + dx, ny = y + dy;
            if(0 <= nx && nx < W && 0 <= ny && ny < H && field[nx][ny] == 1) dfs(nx, ny);
        }
    }
 
    return ;
}
 
int main(){
    while(1){
        int res = 0;
        input();
        if(W == 0 && H == 0) break;
 
        for(int i = 0;i < H;i++){
            for(int j = 0;j < W;j++){
                if(field[j][i] == 1){
                    dfs(j, i);
                    res++;
                }
            }
        }
 
        cout << res << endl;
    }
 
    return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

int h, w;
vector<vector<int> > field, visited;
bool out_field(int i, int j) { return i < 0 || i >= h || j < 0 || j >= w; }

void dfs(int i, int j) {
    if (i < 0 || i >= h || j < 0 || j >= w) return;
    if (visited[i][j] == true) return;
    visited[i][j] = true;
    if (field[i][j] == 0) return;
    for (int di = -1; di < 2; di++) {
        for (int dj = -1; dj < 2; dj++) {
            int ni = i + di, nj = j + dj;
            dfs(ni, nj);
        }
    }
}

int main() {
    while (cin >> w >> h) {
        if (w == 0) break;
        field.assign(h, vector<int>(w));
        visited.assign(h, vector<int>(w));
        for (int i = 0; i < h; i++) {
            for (int j = 0; j < w; j++) {
                cin >> field[i][j];
            }
        }
        int cnt = 0;
        for (int si = 0; si < h; si++) {
            for (int sj = 0; sj < w; sj++) {
                if (field[si][sj] == 1 && visited[si][sj] != 1) {
                    dfs(si, sj);
                    cnt++;
                }
            }
        }
        cout << cnt << endl;
    }
    return 0;
}

C++: #include <iostream>

#define W_MAX 52
#define H_MAX 52

void dfs(int f[H_MAX][W_MAX], int y, int x);

using namespace std;

int main(void)
{
	int w,h;

	int i1,i2;
	int count;

	int f[H_MAX][W_MAX];

	while(1){
		cin >> w >> h;
		if(w==0 && h==0) break;

		for(i1=0;i1<H_MAX;i1++){
			for(i2=0;i2<W_MAX;i2++){
				f[i1][i2] = 0;
			}
		}

		for(i1=1;i1<=h;i1++){
			for(i2=1;i2<=w;i2++){
				cin >> f[i1][i2];
			}
		}

		count=0;
		for(i1=1;i1<=h;i1++){
			for(i2=1;i2<=w;i2++){
				if(f[i1][i2]==1){
					count++;
					dfs(f,i1,i2);
				}
			}
		}

		cout << count << endl;
		
	}

	return 0;
}

void dfs(int f[H_MAX][W_MAX],int y,int x)
{
	int i1,i2;

	f[y][x] = 0;
	for(i1=-1;i1<2;i1++){
		for(i2=-1;i2<2;i2++){

			if(f[y+i1][x+i2]==1) dfs(f,y+i1,x+i2);
		}
	}
	return;
}

C++: #include <bits/stdc++.h>
using namespace std;
#define repr(i, a, b) for (int i = a; i < b; i++)
#define rep(i, n) for (int i = 0; i < n; i++)
typedef long long ll;
#define mod 1000000007

ll gcd(ll x,ll y) {return y ? gcd(y,x%y) : x;} 
ll lcm(ll x,ll y) {return x/gcd(x,y)*y;}

int mp[51][51];
int cnt;
int w,h;

void dfs(int x,int y){
    mp[x][y]=0;
    for(int i=-1;i<=1;i++){
        for(int j=-1;j<=1;j++){
            if(x+i<0||h<=x+i||y+j<0||w<=y+j) continue;
            if(mp[x+i][y+j]) dfs(x+i,y+j);
        }
    }
}

int main(){
    while(1){
        cin >> w >> h;
        if(w==0&&h==0) break;
        for(int i=0;i<h;i++){
            for(int j=0;j<w;j++){
                cin >> mp[i][j];
            }
        }
        cnt=0;
        rep(i,h)rep(j,w){
            if(mp[i][j]){
                cnt++;
                dfs(i,j);
            }
        }
        cout << cnt << endl;
    }
    
    return 0;
}