Go: package main

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

var sc = bufio.NewScanner(os.Stdin)
var route [][]int

func scanInt() int {
	num, _ := strconv.Atoi(scanString())
	return num
}

func scanString() string {
	sc.Scan()
	return sc.Text()
}

func init() {
	sc.Split(bufio.ScanWords)
}

func dfs(h, w int) {
	if route[h][w] == 0 {
		return
	}

	route[h][w] = 0
	for _, x := range []int{-1, 0, 1} {
		for _, y := range []int{-1, 0, 1} {
			if route[h+x][w+y] == 0 {
				continue
			}
			dfs(h+x, w+y)
		}
	}
}

func main() {
	writer := bufio.NewWriter(os.Stdout)
	for {
		w, h := scanInt(), scanInt()
		if w == 0 && h == 0 {
			break
		}

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

		total := 0
		for i := 1; i <= h; i++ {
			for j := 1; j <= w; j++ {
				if route[i][j] == 1 {
					total++
					dfs(i, j)
				}
			}
		}
		fmt.Fprintln(writer, total)
	}
	writer.Flush()
}

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

/*bool check(const int x, const int y, const int LandNum, const int aNodeCol[50][50], const int aXMax, const int aYMax){
	if ((x<0 || x >= aXMax) || (y<0 || y >= aYMax) || (aNodeCol[x][y] != 1)){
		return false;
	}
	return true;
}*/

bool LandConfirmedAndMawariCheck(const int x, const int y, const int LandNum, int aNodeCol[50][50], const int aXMax, const int aYMax){
	if (aNodeCol[x][y] == 1){
		aNodeCol[x][y] = LandNum;
		/*if (check(x - 1, y, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x - 1, y, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x - 1, y - 1, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x - 1, y - 1, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x - 1, y + 1, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x - 1, y + 1, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x + 1, y - 1, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x + 1, y - 1, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x + 1, y, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x + 1, y, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x + 1, y + 1, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x + 1, y + 1, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x, y - 1, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x, y - 1, LandNum, aNodeCol, aXMax, aYMax);
		if (check(x, y + 1, LandNum, aNodeCol, aXMax, aYMax))LandConfirmedAndMawariCheck(x, y + 1, LandNum, aNodeCol, aXMax, aYMax);*/
		if (!((x - 1<0 || x - 1 >= aXMax) || (y    <0 || y     >= aYMax) || (aNodeCol[x-1][y    ] != 1)))LandConfirmedAndMawariCheck(x - 1, y    , LandNum, aNodeCol, aXMax, aYMax);
		if (!((x - 1<0 || x - 1 >= aXMax) || (y - 1<0 || y - 1 >= aYMax) || (aNodeCol[x-1][y - 1] != 1)))LandConfirmedAndMawariCheck(x - 1, y - 1, LandNum, aNodeCol, aXMax, aYMax);
		if (!((x - 1<0 || x - 1 >= aXMax) || (y + 1<0 || y + 1 >= aYMax) || (aNodeCol[x-1][y + 1] != 1)))LandConfirmedAndMawariCheck(x - 1, y + 1, LandNum, aNodeCol, aXMax, aYMax);
		if (!((x + 1<0 || x + 1 >= aXMax) || (y - 1<0 || y - 1 >= aYMax) || (aNodeCol[x+1][y - 1] != 1)))LandConfirmedAndMawariCheck(x + 1, y - 1, LandNum, aNodeCol, aXMax, aYMax);
		if (!((x + 1<0 || x + 1 >= aXMax) || (y    <0 || y     >= aYMax) || (aNodeCol[x+1][y    ] != 1)))LandConfirmedAndMawariCheck(x + 1, y    , LandNum, aNodeCol, aXMax, aYMax);
		if (!((x + 1<0 || x + 1 >= aXMax) || (y + 1<0 || y + 1 >= aYMax) || (aNodeCol[x+1][y + 1] != 1)))LandConfirmedAndMawariCheck(x + 1, y + 1, LandNum, aNodeCol, aXMax, aYMax);
		if (!((x    <0 || x     >= aXMax) || (y - 1<0 || y - 1 >= aYMax) || (aNodeCol[x  ][y - 1] != 1)))LandConfirmedAndMawariCheck(x    , y - 1, LandNum, aNodeCol, aXMax, aYMax);
		if (!((x    <0 || x     >= aXMax) || (y + 1<0 || y + 1 >= aYMax) || (aNodeCol[x  ][y + 1] != 1)))LandConfirmedAndMawariCheck(x    , y + 1, LandNum, aNodeCol, aXMax, aYMax);
		return true;
	}
	return false;
}



int main(void){
	int NodeCol[50][50];
	int a, b, c;
	int XMax, YMax;
	while(1){
		cin >> a >> b;
		if (a == 0&&b == 0)break;
		XMax = a; YMax = b;

		for (int Lone = 0;  Lone < XMax; ++Lone){
			for (int Ltwo = 0; Ltwo < YMax; ++Ltwo){
				cin >> c;
				NodeCol[Lone][Ltwo] = c;
			}
		}
		int t = 2;
		for (int Lone = 0;  Lone < XMax; ++Lone){
			for (int Ltwo = 0; Ltwo < YMax; ++Ltwo){
				if (NodeCol[Lone][Ltwo]==1)
				{
					if (LandConfirmedAndMawariCheck(Lone, Ltwo, t, NodeCol, XMax, YMax))t++;
				}
			}
		}
		cout << t-2<<endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>

#define M_PI       3.14159265358979323846   // pi

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<ll> VI;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, ll, ll> t4;
typedef tuple<ll, ll, ll, ll, ll> t5;

#define rep(a,n) for(ll a = 0;a < n;a++)
#define repi(a,b,n) for(ll a = b;a < n;a++)

using namespace std;

static const ll INF = 1e15;

struct UnionFind {
public:
	vector <ll> par; // 
	vector <ll> siz; // 

	UnionFind() {}

	UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) {
		for (ll i = 0; i < sz_; ++i) par[i] = i;
	}
	void init(ll sz_) {
		par.resize(sz_);
		siz.assign(sz_, 1LL);
		for (ll i = 0; i < sz_; ++i) par[i] = i;
	}

	ll root(ll x) {
		while (par[x] != x) {
			x = par[x] = par[par[x]];
		}
		return x;
	}

	bool merge(ll x, ll y) {
		x = root(x);
		y = root(y);
		if (x == y) return false;
		if (siz[x] < siz[y]) swap(x, y);
		siz[x] += siz[y];
		par[y] = x;
		return true;
	}

	bool issame(ll x, ll y) {
		return root(x) == root(y);
	}

	ll size(ll x) {
		return siz[root(x)];
	}
};

int main() {
	while (true) {
		ll w, h;
		cin >> w >> h;
		if (w == 0 && h == 0) return 0;
		vector<vector<int>> grid(h, vector<int>(w, 0));
		rep(i, h) {
			rep(j, w) {
				cin >> grid[i][j];
			}
		}

		vector<vector<int>> root(h, vector<int>(w, -1));

		function<void(int, int, int)> dfs = [&](int x, int y, int parent) {
			if (root[y][x] >= 0) return;
			if (!grid[y][x]) return;
			root[y][x] = parent;
			P shifts[] = {
				{0,1},{-1,1},{-1,0},{-1,-1},
				{0,-1},{1,-1},{1,0},{1,1},
			};
			for (auto p : shifts) {
				auto nx = x + p.first;
				auto ny = y + p.second;
				if (nx >= 0 && nx < w) {
					if (ny >= 0 && ny < h) {
						if(grid[ny][nx]) dfs(nx, ny, parent);
					}
				}
			}
		};
		rep(i, h) {
			rep(j, w) {
				dfs(j, i, i * w + j);
			}
		}

		unordered_set<ll> u;
		rep(i, h) {
			rep(j, w) {
				if (grid[i][j]) {
					u.insert(root[i][j]);
				}
			}
		}
		cout << u.size() << endl;
	}
	return 0;
}

C++: #include<iostream>
#include<cstdio>
using namespace std;
int mas[100][100];
int dx[8]={1,1,0,-1,-1,-1,0,1},dy[8]={0,1,1,1,0,-1,-1,-1};
int sx,sy,gx,gy,w,h,cnt=0;
void dfs(int x,int y);
int main(){
  while(1){
    cnt=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 >> mas[i][j];
    }
  }
  for(int i=0;i<h;i++){
    for(int j=0;j<w;j++){
      if(mas[i][j]==1){
        cnt++;
        dfs(j,i);
      }
    }
  }
  cout << cnt << endl;
  }
}
void dfs(int x,int y){
  mas[y][x]=0;
  for(int i=0;i<8;i++){
    int nx=x+dx[i];
    int ny=y+dy[i];
    if(nx >= 0&& nx < w && ny >= 0 && ny < h && mas[ny][nx]==1){
        dfs(nx,ny);
      }
  }
}