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>
#include <utility>
using namespace std;
typedef pair<int, int> P;

const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

int main()
{
    while(true){
        int w, h;
        cin >> w >> h;
        if(w == 0 && h == 0) break;
        int c[53][53];
        for(int j = 0; j < w + 2; j++){
            c[0][j] = c[h + 1][j] = 0;
        }
        for(int i = 1; i <= h; i++){
            c[i][0] = c[i][w + 1] = 0;
            for(int j = 1; j <= w; j++) cin >> c[i][j];
        }
        queue<P> que;
        int ans = 0;
        for(int i = 1; i <= h; i++){
            for(int j = 1; j <= w; j++){
                if(c[i][j] == 1){
                    c[i][j] = 0;
                    que.push(P(i, j));
                    while(que.size()){
                        int x = que.front().first;
                        int y = que.front().second;
                        que.pop();
                        for(int k = x - 1; k <= x + 1; k++){
                            for(int l = y - 1; l <= y + 1; l++){
                                if(c[k][l] == 1){
                                    c[k][l] = 0;
                                    que.push(P(k, l));
                                }
                            }
                        }
                    }
                    ans++;
                }
            }
        }
        cout << ans << endl;
    }
}

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 && 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 <bits/stdc++.h>
#define REP(i, n) for (int i = 0; i < n; i++)
#define FOR(i, m, n) for (int i = m; i < n; i++)
#define ALL(v) (v).begin(), (v).end()
#define coutd(n) cout << fixed << setprecision(n)
#define ll long long int
#define vl vector<ll>
#define vi vector<int>
const int INF = 2147483647;
const ll MOD = 1000000007;

using namespace std;

void dfs(const int i, const int j, const int h, const int w, const vector<vi> &grid, vector<vector<bool>> &visited) {
  if (not(0 <= i and i < h and 0 <= j and j < w))
    return;
  if (visited[i][j] or grid[i][j] == 0)
    return;
  visited[i][j] = true;
  int dx[8] = {1, 1, 0, -1, -1, -1, 0, 1};
  int dy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
  REP(k, 8) { dfs(i + dx[k], j + dy[k], h, w, grid, visited); }
}

int main() {
  while (true) {
    int w, h;
    cin >> w >> h;
    if (w == 0 and h == 0)
      return 0;
    vector<vi> grid(h, vi(w, 0));
    vector<vector<bool>> visited(h, vector<bool>(w, false));
    REP(i, h) {
      REP(j, w) { cin >> grid[i][j]; }
    }

    int ans = 0;
    REP(i, h) {
      REP(j, w) {
        if (not visited[i][j] and grid[i][j] == 1) {
          ans++;
          dfs(i, j, h, w, grid, visited);
        }
      }
    }
    cout << ans << endl;
  }
  return 0;
}