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 <stack>
#include <queue>
#include <vector>
using namespace std;

int MAP(vector<vector<int>> &m, int i, int j){
	int w = m[0].size();
	int h = m.size();

	if(!(0 <= i && i < h && 0 <= j && j < w)){
		return 0;
	}

	if(m[i][j] == 0){
		return 0;
	}
	else if(m[i][j] = 1){
		m[i][j] = 0;
		MAP(m, i - 1, j - 1);
		MAP(m, i, j - 1);
		MAP(m, i + 1, j - 1);
		MAP(m, i - 1, j);
		MAP(m, i + 1, j);
		MAP(m, i - 1, j + 1);
		MAP(m, i, j + 1);
		MAP(m, i + 1, j + 1);
	}
	return 1;
}

int main(){
	int w, h;

	while(true){
		int count = 0;
		cin >> w >> h;

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

		vector<vector<int> > map(h, vector<int>(w, 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++){
				count += MAP(map, i , j);
			}
		}

		cout << count << endl;
	}
}

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

using namespace std;
using vec = vector<int>;
using mat = vector<vec>;

void init(vec & parent)
{
	for (int i = 0; i < parent.size(); ++i)
	{
		parent[i] = i;
	}
}

int find(vec & parent, int x)
{
	if (parent[x] == x)return x;
	return parent[x] = find(parent, parent[x]);
}

void unite(vec & parent, int x, int y)
{
	x = find(parent, x);
	y = find(parent, y);
	if (x == y)return;
	parent[y] = x;
}

int change(int y, int x, int W)
{
	return y*W + x;
}


int main()
{
	while (true)
	{
		int w, h;
		cin >> w >> h;

		if (w == 0 && h == 0)return 0;

		mat c(h, vec(w));
		vec parent(h*w);

		init(parent);

		for (int y = 0; y < h; ++y)
		{
			for (int x = 0; x < w; ++x)
			{
				cin >> c[y][x];

				if (x != 0 && c[y][x] == c[y][x - 1])
				{
					unite(parent, change(y, x, w), change(y, x - 1, w));
				}
				if (y != 0 && c[y][x] == c[y - 1][x])
				{
					unite(parent, change(y, x, w), change(y - 1, x, w));
				}
				if (x != 0 && y != 0 && c[y][x] == c[y - 1][x - 1])
				{
					unite(parent, change(y, x, w), change(y - 1, x - 1, w));
				}
				if (x != w - 1 && y != 0 && c[y][x] == c[y - 1][x + 1])
				{
					unite(parent, change(y, x, w), change(y - 1, x + 1, w));
				}
			}
		}

		int ans = 0;
		for (int y = 0; y < h; ++y)
		{
			for (int x = 0; x < w; ++x)
			{
				int i = change(y, x, w);
				ans += parent[i] == i && c[y][x] == 1;
			}
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
//入力
int H,W;
vector<vector<int>> field;

void dfs(int h,int w){
  field[h][w] = 0;
  // 八方向を探索
  for(int dh=-1;dh<=1;dh++){
    for(int dw=-1;dw<=1;dw++){
      int nh = h+dh,nw=w+dw;
      //場外アウトしたり、0だったりはスルー
      if(nh<0||nh>=H||nw<0||nw>=W) continue;
      if(field[nh][nw]==0) continue;
      dfs(nh,nw);//再帰的に探索
    }
  }
}

int main(){
  //入力受け取り
  while(cin >> W >> H){
    if(H==0||W==0) break;
    field.assign(H,vector<int>(W,0));
    for(int h=0;h<H;h++)for(int w=0;w<W;w++) cin >> field[h][w];
    int count = 0;
    for(int h=0;h<H;h++){
      for(int w=0;w<W;w++){
        if(field[h][w]==0) continue;//残島じゃなかったらスルー
        dfs(h,w);
        ++count;
      }
    }
    cout << count << endl;
  }
}