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>
#include <queue>
using namespace std;

int w, h, c, n;
int a[50][50];
queue<int> q;

void bfs() {
	int x, y;
	while (1) {
		x = q.front() % w;
		y = q.front() / w;
		
		if ( x > 0 && y > 0 && a[y - 1][x - 1] == 1 ) {
			a[y - 1][x - 1] = 0;
			q.push( ( y - 1 ) * w + x - 1 );
		}
		if ( x < w - 1 && y > 0 && a[y - 1][x + 1] == 1 ) {
			a[y - 1][x + 1] = 0;
			q.push( ( y - 1 ) * w + x + 1 );
		}
		if ( x > 0 && y < h - 1 && a[y + 1][x - 1] == 1 ) {
			a[y + 1][x - 1] = 0;
			q.push( ( y + 1 ) * w + x - 1 );
		}
		if ( x < w - 1 && y < h - 1 && a[y + 1][x + 1] == 1 ) {
			a[y + 1][x + 1] = 0;
			q.push( ( y + 1 ) * w + x + 1 );
		}
		if ( x > 0 && a[y][x - 1] == 1 ) {
			a[y][x - 1] = 0;
			q.push( y * w + x - 1 );
		}
		if ( y > 0 && a[y - 1][x] == 1 ) {
			a[y - 1][x] = 0;
			q.push( ( y - 1 ) * w + x );
		}
		if ( x < w - 1 && a[y][x + 1] == 1 ) {
			a[y][x + 1] = 0;
				q.push( y * w + x + 1 );
		}
		if ( y < h - 1 && a[y + 1][x] == 1 ) {
			a[y + 1][x] = 0;
			q.push( ( y + 1 ) * w + x );
		}
		q.pop();
		if ( q.empty() ) break;	
	}
	n++;
}

int main() {

	while (1) {
		n = 0;
		for ( int j = 0; j < 50; j++ )
			for ( int i = 0; i < 50; i++ )
				a[j][i] = 0;
		cin >> w >> h;
		if ( w == 0 ) break;
		for ( int j = 0; j < h; j++ ) {
			for ( int i = 0; i < w; i++ ) {
				cin >> c;
				a[j][i] = c;
			}
		}
		for ( int j = 0; j < h; j++ ) {
			for ( int i = 0; i < w; i++ ) {
				if ( a[j][i] == 1 ) {
					a[j][i] = 0;
					q.push( j * w + i );
					bfs();
				}
			}
		}
		cout << n << endl;
	}
}

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

int x,y;
int ti[51][51];
const int dx[]={1,0,-1,0,-1,1,-1,1}, dy[]={0,-1,0,1,-1,1,1,-1};

bool valid(int i,int j)
{
	return(i>=0&&i<y&&j>=0&&j<x);
}

int bfs(int m,int n)
{
	if(ti[m][n]==0)
      return 0;
    queue< pair<int,int> > Q;
	pair<int,int> a,b;
	a.first=m;
	a.second=n;
	Q.push(a);
	while(!Q.empty())
	{
		a=Q.front();
		Q.pop();
		for(int i=0;i<8;i++)
		{
			b.first=a.first+dx[i];
			b.second=a.second+dy[i];
			if(valid(b.first, b.second) && ti[b.first][b.second])
			{
				ti[b.first][b.second]=0;
				Q.push(b);
			}
		}
	}
	return 1;
}

int main()
{
	while(cin >> x >> y)
	{
		if(!x&&!y)
		  break;
		for(int i=0;i<y;i++)
		   for(int j=0;j<x;j++)
		   {
		   	    cin >> ti[i][j];
		   }
        int sum=0;
        for(int i=0;i<y;i++)
		   for(int j=0;j<x;j++)
              if(bfs(i,j))
              {
                  sum++;
              }
        cout << sum << endl;
	}
}

C++: #define _USE_MATH_DEFINES
#define INF 100000000

#include <iostream>
#include <sstream>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>
#include <map>
#include <string>
#include <cstring>
#include <set>
#include <deque>
#include <bitset>
#include <list>
#include <cctype>
#include <utility>

using namespace std;

typedef long long ll;
typedef pair <int,int> P;
typedef pair <int,P> PP;

static const double EPS = 1e-8;

int stage[50][50];

void dfs(int x,int y,int w,int h){
	stage[y][x] = 0;
	for(int tx=-1;tx<=1;tx++){
		for(int ty=-1;ty<=1;ty++){
			int dx = x + tx;
			int dy = y + ty;
			if(dx < 0 || dx >=w || dy < 0 || dy >= h) continue;

			if(stage[dy][dx]==1){
				dfs(x+tx,y+ty,w,h);
			}
		}
	}
}

int main(){
	int w,h;
	while(~scanf("%d %d",&w,&h)){
		if(w==h && h==0) break;
		for(int y=0;y<h;y++){
			for(int x=0;x<w;x++){
				scanf("%d",(*(stage+y)+x));
			}
		}

		int res=0;
		for(int y=0;y<h;y++){
			for(int x=0;x<w;x++){
				if(stage[y][x]==1){
					dfs(x,y,w,h);
					res++;
				}
			}
		}

		printf("%d\n",res);
	}
}