Go: package main

import (
	"bufio"
	"fmt"
	"io"
	"math"
	"os"
	"strconv"
)

var (
	readString func() string
	readBytes  func() []byte
	stdout     *bufio.Writer
)

func init() {
	readString, readBytes = newReadString(os.Stdin)
	stdout = bufio.NewWriter(os.Stdout)
}

func newReadString(ior io.Reader) (func() string, func() []byte) {
	r := bufio.NewScanner(ior)
	r.Buffer(make([]byte, 1024), math.MaxInt32)
	r.Split(bufio.ScanWords)

	f1 := func() string {
		if !r.Scan() {
			panic("Scan failed")
		}
		return r.Text()
	}
	f2 := func() []byte {
		return []byte(f1())
	}
	return f1, f2
}

func readInt() int {
	return int(readInt64())
}

func readInt64() int64 {
	i, err := strconv.ParseInt(readString(), 10, 64)
	if err != nil {
		panic(err.Error())
	}
	return i
}

func readFloat64() float64 {
	f, err := strconv.ParseFloat(readString(), 64)
	if err != nil {
		panic(err.Error())
	}
	return f
}

func printf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(stdout, f, args...)
}

func println(args ...interface{}) (int, error) {
	return fmt.Fprintln(stdout, args...)
}

func eprintln(args ...interface{}) (int, error) {
	return fmt.Fprintln(os.Stderr, args...)
}

func eprintf(f string, args ...interface{}) (int, error) {
	return fmt.Fprintf(os.Stderr, f, args...)
}

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

func min64(a, b int64) int64 {
	if a < b {
		return a
	}
	return b
}

func max(a, b int) int {
	if a < b {
		return b
	}
	return a
}

func max64(a, b int64) int64 {
	if a < b {
		return b
	}
	return a
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

func abs64(a int64) int64 {
	if a < 0 {
		return -a
	}
	return a
}

func gcd(a, b int) int {
	if b == 0 {
		return a
	}
	return gcd(b, a%b)
}

func gcd64(a, b int64) int64 {
	if b == 0 {
		return a
	}
	return gcd64(b, a%b)
}

// readString() string
// readInt() int
// readInt64() int64
// readFloat64() float64

// -----------------------------------------------------------------------------

func main() {
	defer stdout.Flush()

	for {
		ans, ok := solve()
		if !ok {
			break
		}
		println(ans)
	}

}

func solve() (int, bool) {
	w := readInt()
	h := readInt()
	if w == 0 && h == 0 {
		return 0, false
	}

	c := make([][]int, h+2)
	c[0] = make([]int, w+2)
	c[h+1] = make([]int, w+2)
	for i := 1; i-1 < h; i++ {
		c[i] = make([]int, w+2)
		for j := 1; j-1 < w; j++ {
			c[i][j] = readInt()
		}
	}

	var ans int
	for i := 1; i-1 < h; i++ {
		for j := 1; j-1 < w; j++ {
			if 0 < c[i][j] {
				ans++
				dfs(c, i, j)
			}
		}
	}
	return ans, true
}

func dfs(c [][]int, y, x int) {
	c[y][x] = 0
	dx := []int{-1, 0, 1, -1, 1, -1, 0, 1}
	dy := []int{-1, -1, -1, 0, 0, 1, 1, 1}
	for i := range dx {
		nx := x + dx[i]
		ny := y + dy[i]
		if 0 < c[ny][nx] {
			dfs(c, ny, nx)
		}
	}
}

// -----------------------------------------------------------------------------

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

int w,h;
int m[50][50];

void solve(int x,int y){
	if(m[y][x] == 1){
		m[y][x] = 0;
		for(int i=-1;i<2;i++){
			for(int j=-1;j<2;j++){
				if(i==0&&j==0){
					continue;
				}
				if(y+i >= 0 && y+i < h && x+j >= 0 && x+j < w){
					solve(x+j,y+i);
				}
			}
		}
	}
}

int main(){
	while(true){
		int count=0;

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

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

		for(int i=0;i<h;i++){
			for(int j=0;j<w;j++){
				if(m[i][j] == 1){
					solve(j,i);
					count++;
				}
			}
		}

		cout << count << endl;
	}
}

C++: #include <iostream>
#include <vector>
using namespace std;
typedef vector<vector<int> > VVI;
typedef vector<vector<bool> > VVB;

int w, h, cnt;

void labeling(VVI& map, VVB& visited, int x, int y) {
    visited[x][y] = true;
    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 (!visited[x+i][y+j] && map[x+i][y+j])
                labeling(map, visited, x+i, y+j);
        }
    }
}

int main(int argc, char *argv[])
{
    while (cin >> w >> h, w | h) {
        VVI map(h, vector<int>(w));
        VVB visited(h, vector<bool>(w, false));
        cnt = 0;
        for (int i = 0; i < h; ++i)
            for (int j = 0; j < w; ++j)
                cin >> map[i][j];
        for (int i = 0; i < h; ++i) {
            for (int j = 0; j < w; ++j) {
                if (!visited[i][j] && map[i][j]) {
                    cnt++;
                    labeling(map, visited, i, j);
                }
            }
        }
        cout << cnt << endl;
    }
    return 0;
}

C++: #include<iostream>
#include<vector>
using namespace std;
int dx[8]={0,1,0,-1,1,1,-1,-1};
int dy[8]={1,0,-1,0,1,-1,1,-1};

bool dfs(int sx,int sy,vector<vector<bool> >&c){
if(c[sx][sy]==false) return false;
c[sx][sy]=false;
for(int i=0;i<8;i++){
int nx=sx+dx[i];
int ny=sy+dy[i];
bool flag=dfs(nx,ny,c);
}
return true;
}

int main(void){
int h,w,temp;
while(1){
cin>>w>>h;
if(w==0) break;
vector<vector<bool> > c(w+2,vector<bool>(h+2,false)) ;
for(int i=1;i<=h;i++){
for(int j=1;j<=w;j++){
cin>>temp;
if(temp==1) c[i][j]=true;
}
}
int t=0;
for(int i=1;i<=h;i++){
for(int j=1;j<=w;j++){
bool flag=dfs(i,j,c);
if(flag) t++;
}
}
cout<<t<<endl;
}
return 0;
}

C++: #include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)n;++i)
#define each(a, b) for(auto (a): (b))
#define all(v) (v).begin(),(v).end()
#define fi first
#define se second
#define pb push_back
#define sint(x) cout <<#x<<" = "<<(x)<<endl
#define spair(p) cout <<#p<<": "<<p.fi<<" "<<p.se<<endl
#define svec(v) cout<<#v<<":";rep(i,v.size())cout<<" "<<v[i];cout<<endl
#define sset(s) cout<<#s<<":";each(i,s)cout <<" "<<i;cout<<endl

using namespace std;

typedef pair<int,int>P;

const int MAX_N = 52;
const int dx[] = {1,1,1,0,0,-1,-1,-1};
const int dy[] = {1,0,-1,1,-1,1,0,-1};

int flag[MAX_N][MAX_N];
int w,h;

void dfs(int u,int v)
{
    flag[u][v] = 0;
    rep(i,8){
        int nu = u + dx[i],nv = v + dy[i];
        if(0 <= nu && nu < h && 0 <= nv && nv < w && flag[nu][nv]){
            dfs(nu,nv);
        }
    }
    return;
}

int main()
{
    while(1){
        cin >> w >> h;
        if(w == 0){
            break;
        }
        rep(i,h){
            rep(j,w){
                cin >> flag[i][j];
            }
        }
        int ans = 0;
        rep(i,h){
            rep(j,w){
                if(flag[i][j] != 0){
                    dfs(i,j);
                    ans++;
                }
            }
        }
        cout << ans << "\n";
    }
}