Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	resolve()
}

func resolve() {
	results := []int{}
	for true {
		w, h := scanInt(sc), scanInt(sc)
		if w == 0 && h == 0 {
			break
		}
		grid := make([][]int, h)
		for i := 0; i < h; i++ {
			grid[i] = make([]int, w)
			for j := 0; j < w; j++ {
				grid[i][j] = scanInt(sc)
			}
		}
		num := 0
		for i := range loop0(h) {
			for j := range loop0(w) {
				start := pos{y: i, x: j}
				if grid[start.y][start.x] == 0 {
					continue
				}
				num++
				_dfs(grid, w, h, start)
			}
		}
		results = append(results, num)
	}
	for _, v := range results {
		fmt.Println(v)
	}
	return
}

func _dfs(grid [][]int, w, h int, start pos) {
	grid[start.y][start.x] = 0
	for _, df := range []pos{
		pos{1, 0}, pos{-1, 0},
		pos{0, -1}, pos{0, 1},
		pos{1, 1}, pos{-1, -1},
		pos{-1, 1}, pos{1, -1},
	} {
		np := addPos(start, df)
		if np.y < 0 || h <= np.y || np.x < 0 || w <= np.x {
			continue
		}
		if grid[np.y][np.x] == 0 {
			continue
		}
		_dfs(grid, w, h, np)
	}
}

type pos struct{ x, y int }

func addPos(p, d pos) pos {
	return pos{
		x: p.x + d.x,
		y: p.y + d.y,
	}
}

func loop0(n int) chan int {
	return loop(0, n-1, 1)
}

func loop1(n int) chan int {
	return loop(1, n, 1)
}

func loop(s, e, d int) chan int {
	ch := make(chan int)
	go func() {
		for i := s; i <= e; i += d {
			ch <- i
		}
		close(ch)
	}()
	return ch
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include <algorithm>
#include <iostream>
#include <vector>
#include <cstring>

using namespace std;


bool done[52][52];
int field[52][52];
int ofs[8][2] = {
  {0, 1},
  {1, 0},
  {-1, 0},
  {0, -1},
  {1, 1},
  {1, -1},
  {-1,-1},
  {-1, 1}
};

void paint(int y, int x)
{
  for (int i = 0; i < 8; ++i) {
    int nx = x + ofs[i][0];
    int ny = y + ofs[i][1];
    if (field[ny][nx] && !done[ny][nx]) {
      done[ny][nx] = true;
      paint(ny, nx);
    }
  }
}

int main() {
  int w, h;
  for(;;) {
    cin >> w >> h;
    if ((w|h) == 0) {
      break;
    }
    memset(field, 0, sizeof(field));
    memset(done, 0, sizeof(done));
    for (int i = 1; i <= h; ++i) {
      for (int j = 1; j <= w; ++j) {
        cin >> field[i][j];
      }
    }
    int cnt = 0;
    for (int i = 1; i <= h; ++i) {
      for (int j = 1; j <= w; ++j) {
        if (field[i][j] && !done[i][j]) {
          paint(i, j);
          ++cnt;
        }
      }
    }
    cout << cnt << endl;
  }
  return 0;
}

C++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <limits>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <functional>
#include <iomanip>

using namespace std;

#ifdef LOCAL
#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
#define eprintf(...) 42
#endif
using ll = long long;
using vll = std::vector<ll>;
using vvll = std::vector<vll>;
using vvvll = std::vector<vvll>;
#define reps(i, S, E) for (ll i = (S); i <= (E); i++)
#define rep(i, N) reps(i, 0, N-1)
#define deps(i, E, S) for (ll i = (E); i >= (S); i--)
#define dep(i, N) deps(i, N-1, 0)
const ll INF = 1LL << 60;
const int INF_INT = 1 << 30;

template<class T> inline bool chmax(T &a, T b) { if (a < b) { a = b; return true; }return false; }
template<class T> inline bool chmin(T &a, T b) { if (a > b) { a = b; return true; }return false; }
struct mll {
	static ll MOD;
	ll val;
	mll(ll v = 0) : val(v % MOD) { if (val < 0) val += MOD; }
	mll operator - () const { return -val; }
	mll operator + (const mll &b) const { return val + b.val; }
	mll operator - (const mll &b) const { return val - b.val; }
	mll operator * (const mll &b) const { return val * b.val; }
	mll operator / (const mll &b) const { return mll(*this) /= b; }
	mll operator + (ll b) const { return *this + mll(b); }
	mll operator - (ll b) const { return *this - mll(b); }
	mll operator * (ll b) const { return *this * mll(b); }
	friend mll operator + (ll a, const mll &b) { return b + a; }
	friend mll operator - (ll a, const mll &b) { return -b + a; }
	friend mll operator * (ll a, const mll &b) { return b * a; }
	mll &operator += (const mll &b) { val = (val + b.val) % MOD; return *this; }
	mll &operator -= (const mll &b) { val = (val + MOD - b.val) % MOD; return *this; }
	mll &operator *= (const mll &b) { val = (val*b.val) % MOD; return *this; }
	mll &operator /= (const mll &b) {
		ll c = b.val, d = MOD, u = 1, v = 0;
		while (d) {
			ll t = c / d;
			c -= t * d; swap(c, d);
			u -= t * v; swap(u, v);
		}
		val = val * u % MOD;
		if (val < 0) val += MOD;
		return *this;
	}
	mll &operator += (ll b) { return *this += mll(b); }
	mll &operator -= (ll b) { return *this -= mll(b); }
	mll &operator *= (ll b) { return *this *= mll(b); }
	mll &operator /= (ll b) { return *this /= mll(b); }
	bool operator == (const mll &b) { return val == b.val; }
	bool operator != (const mll &b) { return val != b.val; }
	bool operator == (ll b) { return *this == mll(b); }
	bool operator != (ll b) { return *this != mll(b); }
	friend bool operator == (ll a, const mll &b) { return mll(a) == b.val; }
	friend bool operator != (ll a, const mll &b) { return mll(a) != b.val; }
	friend ostream &operator << (ostream &os, const mll &a) { return os << a.val; }
	friend istream &operator >> (istream &is, mll &a) { return is >> a.val; }
	static mll Combination(ll a, ll b) {
		chmin(b, a - b);
		if (b < 0) return mll(0);
		mll c = 1;
		rep(i, b) c *= a - i;
		rep(i, b) c /= i + 1;
		return c;
	}
};
using vmll = std::vector<mll>;
using vvmll = std::vector<vmll>;
using vvvmll = std::vector<vvmll>;
using vvvvmll = std::vector<vvvmll>;

struct Fast {
	Fast() {
		cin.tie(0);
		ios::sync_with_stdio(false);
		cout << fixed << setprecision(std::numeric_limits<double>::max_digits10);
	}
} fast; //cin,cout高速化のおまじない＋桁数指定

ll mll::MOD = (ll)(1e9 + 7);// 998244353ll;


vvll g; //グリッドグラフ
vvll f; //発見済み
ll W;
ll H;
void DFS(ll y, ll x) {
	reps(j, -1, 1) reps(i, -1, 1) {
		ll v = y + j;
		ll u = x + i;
		if (v < 0 || u < 0 || v >= H || u >= W) {
			continue;
		}

		if (g[v][u] == 0 || f[v][u] > 0) {
			continue;
		}

		f[v][u] = 1;
		DFS(v, u);
	}
}

int main() {
	while (true) {
		cin >> W;
		cin >> H;

		if (W == 0 && H == 0) {
			break;
		}

		g.clear();
		f.clear();
		g.resize(H);
		f.resize(H);
		rep(i, H) {
			g[i].resize(W);
			f[i].resize(W, 0);
		}
		rep(j, H) rep(i, W) {
			cin >> g[j][i];
		}

		ll result = 0;

		rep(j, H) rep(i, W) {
			if (g[j][i] > 0 && f[j][i] == 0) {
				result++;
				f[j][i] = 1;
				DFS(j, i);
			}
		}

		cout << result << endl;
	}

	return 0;
}

C++: #include <iostream>

#define MAX_NM 50

using namespace std;

void solve();
void dfs(int x, int y);

int w,h;
int field[MAX_NM][MAX_NM];

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>>field[i][j];
            }
        }
        solve();
    }
    return 0;
}

void solve()
{
    int count=0;
    for (int i=0; i<h; i++) {
        for (int j=0; j<w; j++) {
            if (field[i][j]==1) {
                dfs(i,j);
                count++;
            }
        }
    }
    cout<<count<<endl;
}

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 (nx>=0&&nx<h&&ny>=0&&ny<w&&field[nx][ny]==1) {
                dfs(nx,ny);
            }
        }
    }
}